Python for absolute beginners

1. 00 Promo: In less than six hour with practical examples, I want to teach you the Python. We start from installing Python and code on Windows, Mac and Linux, and we start learning about variables. How to use CMD command prompt and all of the systems, learn about operations, everything about strings, list, topple dictionaries, set, map filters, comparisons, chain comparison, lots of options with loops like four loop, y loop, after all of these basics, we go for functions. We will see lots of examples of how we can create a function. After that, we learn about Lambda expressions, and at the end, you are ready to completely do lots of projects. And throughout this course, we will create a practical example of calculating a DMI of a person, so we can tell them if they are fat or if they are not. So without any further ado, let's begin. 2. 01 Download install pyton on windows: For learning Python, first thing that you want to do, we want to download the Python and install it. So let's see how we can do that first. So for downloading Python in Windows, I'm using Windows 11, in the Google, just search for Python. First result that comes up, just click on it. And in here, go to Download Hover over Download, and you can see the Python latest version. The most latest stable version. Of course, there is newer version as well, but this is the more stable version. Based on the time that you want to download this Python, it may be in another version, but if it has three in it, three doesn't matter what comes after that, you can continue with this course easily. But if you want to just exactly use the same version that I'm using, you can click on the download all releases. And in here, in category of looking for a specific releases, you can see all the releases will be here until 2001, and you can see the download there. No, we want to download the Python 3.13 0.3. So click on it, and it will start downloading. And you can it's downloading. With that download it, click on it to open it. And in here, it's really important to enable both of these to add the Python to the path environment path of our Windows. Next, I want to use customized installation, and in here, make sure everything is selected, head next. And in here, I want to tell it to install Python for all the users, and that's it. We can hit install, and it will start installing Python. And now you can see the setup was successful. You can just close it. No for testing it. Hit Windows key on your keyword and search for CMD or Command Prompt. Click on it. And in here, if you write PY for Python and hit Enter, it should go inside the Python and it should show the version that we did in install. Now, let me create another tab in here. There is other ways to go into the Python as well. We can just search for Python. And again, you can see it will go to Python, and it will show us the version. With that, we are inside the Python. If we want to get out of the Python, we can say exit, and it will exit to root path of our user again. No, we didn't install Python and we check if it is installed successfully. 3. 02 Download Install VSCode on windows: No next thing that we want to do so we'll be able to write some code. We need a ID. An ID, it's like a notepad that we can write some code inside it and it will have lots of options. So we can write our code more easily, like autocomplete, like color coding and all of that. So no, let me close this, close all. And in here, in Google, just search for VS code. Of course, there are a lot more like sublime, Pycharm and all of that, but the visual do code is from Microsoft, and I think with the plugins that it has, it will help us a lot. So just go to code.visualstudio.com, the first result in here, and in here, you can click on Download for Window. And it will start the download automatically. You can see it over here. It's like 100 megabyte. No, with the VS code, download it, just click on it, and it will start the installing process. In here, say I accept Head next and leave everything in here to be checked by defaulted Ts, head next, and head in install. That's it. It will be installed now. Now, in here, we can just check this launch Visual Studio code and head finished, and it will open up the Visual Studio code. In here, if you have this, it says restricted mode is intended for safe code browsing. Trust this window to enable all features, click on the manage and click on the Trust, and that's it. The problem will go away. And in here, let me close everything. You can see this should be the first thing that you always see when you open the visual studio code. Now we can click in here, so we'll be able to open folder and create projects. Next, we have a search in here. After that, we have source control, like Github, and after that, we have debugging, and after that, we have some debug. For example, in here, I want to search for Python, and you can see, first thing that it's come up, it's from Microsoft and you can click on it and see the things there. It's called Python extension for Visual Studio code. So this plugin will help us to write code in Python more easily. If this extension was installed before, that's okay. By default for me was installed. I did uninstall it. I wanted to show you how you can install it. Just in here, head in install, and that's it. It will be installed. Now everything is ready. 4. 03 Hello world Code in windows: No with VS code in Installed and Python in assault, let's see how we can write a little bit of code. So in here, I want to go to the explorer, and in here, we can just click on Open folder. But before doing that, I want to go to our desktop. And in here, I want to right click Go to New and create a new folder. And I want to call it Python Projects. Now with this folder created, we can go to here and open that up in here. Go to desktop and open up Python project, head select, and now you can see we are inside that folder, and we can click on Nu to create a new file. For example, a Python file. So click in here, it will tell us what do you want to create? We want to say, create a Python file. That's it. No, first thing that you want to do in here, we want to use Control S on or keyboard to save it. And by default, you can see at the extension, it says PY. So whatever file that you have, at the end of it has PY, it means it is a Python file or Python project. So now, in here, what I want to do I want to call this hello word, right? Just save it with hello word. In here, first thing that I want to write is a print, right? Just print with open and close parentheses, and you can see because we did install the Python plugin, that's why it helps us what it is. It will bring us the documentation, right? So always, you can use this plugin as a documentation. But for now, just don't mind this. You don't need to be worried about it. I will explain how you can use these kind of things. No, in here, I want to just say hello word, and I need to do it inside double quotation. Let me zoom in here like this and make this a little bit smaller. Again zoom a little bit. Now, you can see it better. We have double quotation, and inside that double quotation, whatever we say, for example, hello word from course, right? It will printed in output for us. But as you can see, there is a circle in here that it is telling us that your file is not saved. You should head Controls to save it, and now you can see that circle go away. No, for running this code that we write in here, there is a couple of ways. Let me zoom again. So you can see everything. Go to terminal and add a new terminal. Now, in here, we want to run this Python code, and how we can do that, first, we need to be inside that folder. Right now, you can see the path that we are inside is our folder, so everything is okay. No, we want to say PY or Python and after that, write the name of the file, hello word. And I don't want to write the whole of it, I can just put the first letter of that and hit Tawan or keyword, and it will put the rest for us. After that, if I hit Inter, you can see at the output, it will say hello word from course. No, we write a code, and we run the code, right? But it's not just this way that we can run over code. There are other ways that I wanted to show you in next video. 5. 04 Use CMD to run python code in windows: There are other ways to run our code inside our Windows. Let me show one of the important one. So for doing that, I will head Windows key, and in here, search for CMD, open the command prompt. If you remember, in here, we could just say PY and with that, if we hit inter, it will go inside the Python itself and it will show us the version of it. I want to get out of it with writing exit, and we are no Go no, you can see the path that we are inside. We are inside the C user Navid, and we want to go inside our desktop because we know that our project is inside or desktop. So how we can do that, we can first check what is the folders that we have inside this Navid folder with DIR, right? With that, it will show us all the folders inside the Navid folder. You can see directory of this path Navid folder, we have these files. These files that have dot at the beginning of it, it means they are hidden, and there are some other folders that we can just use Windows Explorer to go to them. Now, you can see we have desktop in here. So we can just say CD and write the desktop. The first letter is more than enough. After that, we can hit tab, so it will write the rest for us. CD desktop, and now you can see the path is C users Navig and desktop. That's it. We are inside the desktop. Let's just see what is the folders inside or desktop with DIR, right? You can see there are a couple of folders. For example, Python projects, and we want to go inside that Python project. So we can say CD Python and head tab and it will put the rest for us. And if you head inter, know you can see we are inside the Python project. Now, again, I want to use DIR to see what files we have inside that. So head Inter, you can see in here, we have a hello word dot PY and know that we are inside this folder and we see this file, we can run it with saying Pi, hello. That's it, head tab, and it put the rest for us. If you hit Inter, no, you can see we run over Python code with command prompt. No, it's a good time to talk more about this command prompt. What other things that we need to know about this CMD, right? So first thing that I want to do, you can see we have lots of text in here, and we want to clear them out. How we can do that, we can write CLS and it Inter and you can see, no we have a clean slate in here. And again, we can run toward code. So we can say Pi Hello, write some part of it, head tab, and it will put the rest for us, and now you can see we are running our code. Next tip about this command prompt that you can do it in terminal in here as well, is that whatever command that you put in here and you head in, it will be saved as well. So with the arrow key, up arrow key, and down arrow key, we can go to those commands, right? So let me delete this for example, I want to run over code one more time. I can hit up arrow key. Again, you can see it will put the Pi helloword dot P for us and we can hit Inter. Again, we can do it really fast. You can see we don't need to write it over and over again. And we can do the same inside or visual studio code as well. In here, we can say CLS, and now you can see, it will clear the terminal for us and we can use up aro ky or down aro ke to go through the commands that we put in there and head in there to run it again. No, we learn about CD how we can go inside the folder, but let's see how we can go back. Let's say in here we are in Python projects folder, and we want to go back to desktop folder. How we can do that, we can say CD double dot just like this. M zoom a little CD, double dot and head Enter, no, you can see we are inside the desktop. And if you hit DIR, write DIR and head Enter, you can see it will show us all the directory, all folders inside our desktop. And again, we can say CD Python and use tab to put the in it. And now you can see, again, we are inside Python project, and we can use CLS again to clear the terminal and everything now works fine. So you can see the command prompt and terminal are exactly the same. Just this one, this terminal is integrated with our visual studio code, and it's much faster. But I think this way is much cooler. 6. 05 Install python on linux: You are using Linux, first thing that you want to do, we want to install Python. And easiest way to do that is with terminal. So open up your terminal. In here, I will search for terminal. In this Linux that I'm using, it's called TLIx, but you can open up your terminal. Just hit Windows key on your keyboard and search for terminal. I will bring up your terminal. In here, first thing first, for installing things, we can say sudo. Psudo is for administrations commands, right? So when you want to install something with psudo, it will be installed. After that, we should say app in install Python tree. And it will tell us to put your password. So let me put it there and know the Python is installed. No, next thing that I want to do I want to install another program that is called Python PIP for downloading all the necessary packages for our Python. This is really important. In Windows, it will do it automatically for us. But in here, we need to say psudo app install. Python three PIP. That's it. Head Inter. And first and first, it will say, do you want to continue download this? You say, why or yes, head Inter, and it will start downloading all the necessary files for our Python PIP. And now you can see the Python and Python PIP is installed. And for checking that, we can say Python three, Head Inter. No, you can see, it's showing us the version. Python 3.13 0.3. And it is the same version that we are using in Windows as well. No, for getting out of the Python because right now we are inside the Python itself. We can say exit. With that, it says, use exit open and close parenthesis or Control D to exit, right? So either we can say exit open and close parenthesis, and it will get out of it. And no again, say Python T and go inside the Python, this time, I want to use Control D to get out of it. So these are some tips that it makes our life very much easier. Know that we didn't install Python, let's see how we can install VS code on Linux. 7. 06 Install VSCode on linux: Now that the Python is installed, we need to install the VS code. So in there, we can write some code for Python. VS code is just like any text editor that have lots of tools, for example, color coding, auto completing and all of that, that we can use to write some Python code. So we need to install. Go back to Firefox. In here, in Google search for VS code, and in here, go to VisualStudo code code editing redefined, right? It's code.visualstudio.com. You can see there is two types of downloading here, one dot db and one dot RPM. One of them is for Debian Obunto and one of them is for Red Hat, Fedora, and so on. Based on your Linux version, download one of them. For example, mine needs a Debian, so click on it to go to download page. It will automatically download it for us. Know that it is downloaded. What I want to do, I want to go back to terminal, and in here, we need to navigate to the download folder. So for doing that, first of all, I want to see where I am. I hit CD, and now you can see, we are enroute, right? Of course, we could just see it, but I wanted to show you with CD again, you will see the path. No, I want to check what is the folders inside the root folder. For that, we say LS, for list all the folders and head inter, no, you can see we have desktop document downloads, music, and all of that. No, I want to go inside to download. How we can do that, we can say CD down and we don't need to write to the end. We can just write some part of it and hit tap Keon or keyword and it will put downloads there for us. Head Inter, no we are inside Downloads folder. Again, in here, I want to use LS to see what folders and files we have inside the download folder. Now, you can see in here, we have the code dot DBN or DEB and we want to install that for installing that we should say sudo DPKgI and the name of the file that you want to install. It's called code, all of these. We don't want to write it completely by yourself. So we write just the code and hit tab on our keyboard and it will put it there. And that's it. Now, if we hit Inter, it will tell us to write your password. Let me put it there and head Enter and know it's starting to install the VS code. No, it is saying the installer would like to add the Microsoft repository and sign in key to update VS code through app, right? So in here, just head Enter and know the install is finished. Now for opening the Visual Studio code, we can just say code in here, head Enter, and know it will open the visual studio code. We can maximize it. Of course, we could just hit Windows key on or keyboard and search for VS code or Visual Studio code and double click on it to open it. But this way of opening it looks more cool, right? So now, with that done, Visual Studio code is install. No, I next video, we will write a hello word code. Let's see how we can do that. Next. 8. 07 Hello world cose in Linux: Know that Visual Studio code is installed, let's just write the first project for us. Before doing that, I want to go to Visual Studio code. Go here at the extensions and install the Python extension. If you click on it, you can see what it can do. It has some autocomplete and some color coding and some debugging stuff, right? So heating install to install it. Now you can see the Python and all the necessary plugins is installed. Now, we can go back in here on this explorer tab. No we can open a folder, but right now, we don't have any folder. We can create a folder inside our desktop. For example, in here, create a new folder, and I want to call it Python Projects, right? With that done, no, we can open the top in our visualsdo code. So in here, click on Open folder, go inside the desktop, go inside Python Project, and hit Open, right? Now we are inside that Python project folder. In here, first thing that it says, it says that, do you want to trust this or not? To access the desktop and all of that, we say we click on this, and after that, yes, I trust the Outer and that's it. Now with that done, we can create some Python files in this folder, right? So click on this plus, and I want to name it hello dot py. Why I'm calling it hello dot PY? Because each one of the Python files should have a extension of dot PY. So Python knows that this is a Python code. So whatever Python project that you have, the extension of it should be dot PY. So Python and Visual Studio code knows about it that it is a Python code. After that, choosing the name dot P, head Enter. And now you can see in here I can write some code. I want to say print this print function, I will explain it a lot more in future. But for now, with it, we can show some string or text at output. And how we can do that, we can do it we put in a text inside the quotation mark inside a open and close parentheses. Let me zoom in here a little bit so you can see it better. Make this small. And no in here, I want to say hello word from course, right? You can see there is a circle in here that it will tell us that this file is not saved. If we hit Control S, that circle will go away and know it is saved. But no, let's see how we can actually run this code. There is some way of doing it. Let me show the first one. For the first one, go to terminal in here and create a new terminal. First thing first that I want to do in here, I want to use LS to list all the files inside this Python project folder. Like this, you can see we Hello dot py. No, I want to run it. We can say Python Tree, hello tab. We will complete it. We don't need to write it completely by ourselves after that head Enter, and you can see it says hello word from course. In Windows, we say PY hello dot pi. But in Linux, we say Python tree, hello dot py. So if you are using Linux wherever I'm using PY, you should use Python Tree. That's the most difference between Linux and windows. Now, you can see we are running our first project. Now, in next do, I want to talk more about this terminal. So I will see you in next. 9. 08 Use Terminal in linux: As you saw, we did run a Python code in the terminal of our visual studio code. No, I want to do it in actual terminal of Linux. So in here, what I want to do, first of all, we are in download folder. I want to go back folder to the root folder. So in here, I can say CD double dot, right, and hit Enter, and now you can see we are in the root folder. We can say LS to list all of the folders and files inside the root folder. No, we want to go to desktop. So in here, I can say D CD desk. You can see I put some letter of it, and no if I head tab, it will put the rest for us. No head inter, you can see we are in desktop folder. And in here, I want to use LS to see what is inside it, and now you can see the Python Project folder is there. No, I want to go to inside that folder. I can just say CD. Python and head tab, and now with head in Inter, we are inside Python projects folder. In there, again, I want to use Ls. Can see we have hello dot py. We can run it. We can say Python, T Hello. Just write some part of it, head tap and it will put it there. Now if I head Enter, you can see it says hello word from course. Cool, right? Now, next thing that I want to talk about is how we can clear up all of these. Right now, it is a mess. We can say clear head Enter. No, you can say everything is clear. Now, let's say we want to run our project again. One way is to write Python three hello dot py. But another way with up arrow key on our keyboard, we can go through all the codes, all the commands that we put in there. Up arrow key and down arrow key. For example, if I head up, you can see it will put the Python tree hello dot py there. And if I head in there, you can see it's running or code. That's it. Now you know how you can run your code inside the terminal and how you can use arrow. 10. 09 Download and install python on MacOS: Now for writing code in Python inside the Mac OS, let's see first how we can install Python. So for doing that, open up your browser and search for Python. And here, let me maximize this. Open up the first thing that comes up, and in here, go to Downloads. And in here, hover over the download and you can see the version over here. You can just click in here to download it. If you don't see the exact same version, but there is a tree in here at the beginning of this number, it is okay. But if you want to just install the same version that I'm using, go down until you see the looking for a specific release. And in here, you can see you can download whatever version you want. You can download version one in view all the releases, right, from 2001 as well. No, what you want to download is just this Python in here. Just click on it. And just with that, the Python will be downloaded. We can just minimize this. Go to finder in here and go to Download folder. And in here, you can see the Python package in here. Don't click on it, and with that, you can see in here, we can just click on Continue. Continue again, continue in here, head agree. No, you can head in astall. After that, it will tell you to put your password there. I put my password and head install software. And it will start installing Python and knowing that the Python is assault and you can just had close in here. It will tell you, do you want to put the Python file into the trash? After installing it, you can just hit move to Trash. And you can see in Download, we don't have it anymore. Let me minimize this, minimize this as well. And for testing that, I want to go to terminal, click on the terminal to open the terminal. Now in here for checking if the Python is installed or not, we can just search for Python three, head Enter, and now you can see. First, it will show us the version that we didn't install, and after that, it will go to Python itself. And for getting out of this Python, you can see by this tree arrow, it means we are in Python. And for getting out of it, we can say exit, open and close practice, and head enter, and now you can see we are out of it. Now, we know we did install Python success 11. 10 Download and install vscode on MacOS: For us to be able to write some Python code, we need IDE, some type of notepad so we can write in it, right? We have lots of ID like sublime, VS code, Microsoft Visual Studio, even notepad Notepad plus plus, you can use whichever you want. But the one that I want to use in this course is called VS code, and we want to install that node. So go to your browser and in here, I want to search for VS code. Right? The first thing that open up is visual CDO code code.visualsd.com. Just click on it, open it, and that's it. In here, you can just click on download for MacOS and tell you download it automatically. And now you can see it start downloading. And now with VS code download it, we can go to Finder in here. And you can see it. It is in Download folder. You can just double click on it to extract it. Now you can see it did extract it and put it over here, and we can open it just like this, but I want to put it in launchpad. For doing that, I want to click on over Finder first, and in here, open up a new finder window. And with this new one, I want to go to applications, and you can see all the application in here. For example, the Python that we installed. Now go to Downloads, hold Command key, select and drag the visual code and go inside the application folder in here and release. And just with that, we did install Visual Studio code. Now, if you go to Launch Pad, you can see the visual stdio code is in here and you can click on it to open it. First time that you open the visual stdio code, it will verify the software, and after that, it will be much faster to open. Now, in here, it will tell us the Visual stdo code is up download it from Internet. Do you want to open it, you had open and no Visual Studio is open. Let me make it maximize and now you can see in here like we have it in Linux and Windows, we have all the tabs, for example, in here, we can open a folder. In here, we can search for stuff. In here, we have Version Control. In here, we have some debugging tools, and in here, we have some extensions and search for Python. Now you can see we have the Python extension. Just click on it, and it will give us some color coding, auto completing, and lots more. So click on Install to install it. It will make our life very much easier. And know with that, the Python extension will be installed. That's it. Now, we can just close it. Close this, close this. You should see something like this when you close everything. You can just click on this one more time, and you will close everything. Next widow, we will write our first Python code together. 12. 11 Hello world code in MacOS: No, W O VS code in a Salt and Python instalt, let's just write or first code. For doing that, I want to go here, click in here. You can see in here, I can open a folder. So first thing, we need a folder. Let me minimize this. Go to finder, go to desktop. B now there is nothing there. So let's just create a new folder, and I want to call it Python projects. It. This is our folder and we can open it in Visual Studio code. So in Visual Studio code, click on Open Folder and go to desktop and click on the Python project, and it will open it. But before it says, do you want to allow? You say hit Ao After that, it will tell you, do you trust the software or not to access your desktop? You say, Yes, I trust this author, right, because it's from Microsoft. In here, we are inside that folder, and we can click on this plus and create a new file. I want to call this one hello dot PY. Why PY because all the Python code should be inside a file that has extension of PY, so it will be runnable. So Visual Studio code and all other software should know it is a Python file, Python codes inside it, right? After that head inter to open it. And in here, the only thing that I want to do, I want to use a print in here, and we open and close parenthesis and double quotation. Okay? Increase the size a little bit so you can see it better. Knowing here whatever I put in there, whenever we run our coat, it will show it to us. For example, let's just say hello word from course, right? That's it. No, you can see because we add something to this file, there is a circle in here, white circle, right? If you go to file and head save or use Command S, it will save it, and now you can see the white circle is not there anymore. Now, let's see how we can actually run this code. For doing that, go to terminal and create a new terminal. It will open it up here. It's like any terminal in our MACS, right? We are inside the Python project folder, so we can just say Python tree. After that, the name of the file that you want to run that is called Hello, we can just put some of it in there and it tab and it will put the rest. Now, if you had in there, you can see at output, it says hello word from course. And now we can do it again, right? We can run it again. So we create a Python file and we write some code inside it, and after that, we run it. Now, next do I want to talk about this terminal more 13. 12 Use terminal in MacOS: No, we want to talk more about the terminal inside MacOS. First of all, we have a terminal in here, right? So in here, first thing that I want to do I want to use CD. So it will show us where we are, and right now we are inside the root folder. And for us to see what folder is inside this root folder, we can say LS, ok. And now you can see it will show us all the folders that is inside the root folder. And what do you want to do? We want to go to desktop and run the hello word project that we create, right? So in here for doing that, we say CD disk. We don't need to write it completely, put some part of it and head tab, and it will put the rest for you. Head ter, no, you can see we are inside the desktop folder. Again, we can use LS to see what folders is and it will tell us, do you want a little terminal to access the desktop? You say Hello, and now you can see inside the desktop, we have Python project. We want to go there. So we say CD. Pi. Just put some of it head tab, and it will put the rest for you, head inter, and now you can see we are inside the Python project. And with that done, again, we can use LS to see what is inside it. You can see we have hello dot py. And in here, we can say Python. Tree. After that, hello head tap to put the rest of it there, head inter. Now, you can see it says hello word from course. You can see we can run Python code just inside the terminal. We don't need the visual diode to run it, right? No, next thing that I want to show you is how we can get back one folder. For example, go to desktop. We can say CD, double.in here, head Enter. No, you can see we are in desktop. Let's say we want to go back one more time. We say CD, dot, dot, and head Enter, right? No, you can see we are in root. Next thing that I want to show you, you can see right now it is a mess in here and I want to clean everything. All of these text, we can say clear and head Enter. No, you can see we have a clean terminal. No, you know how you can use terminal inside Mac OS. That's more than enough. 14. 13 Operators and priority of them: No before going and write some cool code, what I want to do I want to show you more thing about Python itself. So for doing that, I want to use Windows key and in here, search for terminal or Command Prompt or CMD, and this will be open. Let me zoom a little bit with Holding Control, and with rotating middle mode, I can zoom in here. Knowing here, I want to go inside the Python. If you are in Windows, as you know, we should write PY, and with that, we will go inside the Python. And with Control D, we can get out of the Python space, right? If you are in Linux or MacOS, you should write Python three. That's the most difference between Windows and MacOS and Linux, right? So remember that for the rest of the course. Now in here, let's just go inside the Python with write in Pi and head Enter and know we are inside the Python, what we can do. Like the Hello Worth project that we done, we can use a print. Open pranxs with a double quotation. We can say hello word, and it needs to be wrapped between two double quotation like this and close pranxs like we did it in IDE, right? If I head inter, Python will run this code and give us the result. You can see the result is in here. But we can do lots more with Python. For example, we can do adding, for example, five plus seven and head enter, it will give us the result. It's like calculator. Next, we can do multiplication, three, multiply by seven, it's 21, you can see it. We can say eight, divide it by two, it will give us four, and you can see whenever we have a operation that has dot zero or dot something on it, it means it is a float value, and I will talk about float value more later. No, for example, let's say 8/3. It will give us 2.6 6665 at the end, right? So this is a float number that is not a hole. This 21 because it doesn't have dot, you know that it is a whole number. But Python for showing it to you that it is a float value or whole number, it will add a dot zero at the end of it. And we can do lots more. For example, substraction eight minus five. It will give us three. Next, we can do a remainder of a division, as well. For example, this 8/3, what it will give us, it will give us 2.6 6665, right? But if we say 8% three, what it will give us, it will give us two. Let me show it in paint so you can understand it better. In here, if we say 8/3, we should say two multiply by three, give us six in here, right? And the remainder will be two, right? So with that percent, we receive the two. Sometimes this is really important. For example, when we want to see if a number is odd or even, for example, we have ten. If we get the remainder, get the person two of it, it will give us zero because five multiply by two, it will be ten, and there is no remainder, right? No, if we have 11/2, it will give us 5.1. But if we say 11%, two, it will give us one. So we can use this percent to check if a number is even or if it is odd. And it doesn't matter how big it is, we can check with percent by two to see if it is odd or even head enter and because it gives us zero, it means this number is even number. And again, let me put another value and person two in here and it will give us one. It means we know that this is odd number. Maybe you say where we can use it, there is lots of places that you can use something like this. Thing that I want to talk about is the priority of operations. For example, we want to say five plus two, multiply by seven plus three, right? What will happen? In Python, we have priority of operators. And if I just search for priority of operators in Python and go to image, you can see the first image in here. That it will tell us that multiplication have highest priority from D plus and minus, and you can see all of them in here. It doesn't matter which one you use. All of them are okay. You can see it over here by clicking here, you can see more if I click in here. So you don't need to remember this stuff because you have Google and you can search for it. So I don't remember this stuff. Now in here, what should happen? As you know, if I go here, let me make this minimize a little bit. What should happen in here first, the multiplication should happen to multiply by seven. Let's see what will happen with the calculator, two multiply by seven. It will give us 14. And after that, let's say plus five plus three, and it will give us 22. If I had Enter, you can see this 22. Why? Because the multiplication will happen first and after that, this plus and this plus will happen, as you can see it in here. The highest priority, as you can see, is the multiplication and after that plus and minus, and you can see it over here. Let's say at some point you want to add these two together and after that, add these two together, and after that result of these two, we want to multiply it together, right? So what you want it to happen, let me show it to you in here. We want to say five plus two, it is seven, and we have seven plus three. It will give us ten. No ten, multiply by seven. I will give us 70, right? So let's say we want to get the result of 70. So first, this adding should happen and after that, this adding and after that, the multiplication. You can see in here the parenthesis has highest priority than the others. And my recommendation is to use parentheses always. It is more readable and easy to develop with it more. Just a big recommendation. Remember that. These parentheses is really important. So in here, we can say open parentheses five plus two close parenss after that multiply by open parents again, seven plus three after that close parenthesis. And if I enter, you can see it will give us 70. So, in my opinion, and my recommendation, you don't need to know about the priority of operators at all. Just use prenss. It will be much easier to read and develop it more in future. So just stick with prances. You don't need to know about these priorities at all after that. And that's it. Now you know about operators and priority of 15. 14 Variable and their rules: No it's time to talk about variables. So why we need to use variables for saving things, for using them later, right? So let's see how we can define a variable. So in here, let's just go inside the Python with writing PY and head Enter. Now we are inside the Python. You can say Mar is equal to 20. Know what will happen if we head inter, Python will create a space inside the RAM and it will save 20 in it. And for accessing that number that is saved inside that part of the Ram, we can say Mvar and Python will go to that address in the Ram and get the number that is saved in there and it will show it to us. So with the variable, we are saving things so we can use them later. But we can save lots of things, lots of different variable type we have in Python. But the naming of them is really important. The name of variable should always start with a letter or underscore. So I can say like this underscore. My ar is equal to 30. You can see, no, I can get that value. My ver and it will give us 30, right? And now, if I say my var without this underscore, it will give us 20 because it is two different variables. No, let me show you some type of variable name that you can't use. Let me clear the screen. The variable name can't start with a number. So if you say two var is equal 20, if I hit inter, you can see it will give us an error, and it will tell us that these two shouldn't be there, right? Don't mind this error that it's saying in here. It's not that smart that knows that you want to create a variable. So just remember this that you can't start a variable name with the number. You can't start it with a dash as well. If I say dash R is equal to 20, if I had inter, again, it will give us an error because you can't start a variable name with the dash. You can't start it with equal as well. Equal equal 20. Right? You can't do that. The variable name should always start with a letter or underscore. Next, our variable name can't have dash inside it. So if I say my var is equal to 20, it will give us error as well. So inside it, you can't have a dash as. You can't have equal plus and all of that. Again, you can't do that. So I can't say M plus ir is equal to 20, and again, it will give us an error. So you can't do that. Now, next thing, you can't have a space inside a variable name. I can't say my space, is equal to 52, for example, if I had Inter, again, it will give us a error. No, what you can do, you can do it like this. My var is equal to 20, right? You can say M underscore var is equal to 20. You can say underscore, M underscore var is equal to 20, right? You can put all of them in upper case, my var is equal to 20. Again, you can see it works the same. And we can put number inside the variable name. My two var is equal 20. Again, this will work as well. My two. Now if I had enter it you was 20. Now, you know, what is the rules about choosing a variable. 16. 15 Variable type: No, we know how we can create variable and how we can create them correctly with the right name. But let's see why we need them and how we should use them. So for doing that, let's just go to Python with writing PY heading. Now in here, I want to say my age is equal to 36. I want to say, my name is equal, double quotation. Write your name and double quotation for closing it. And Python with this double quotation around a text, it knows that it is a string, right, and it can be saved inside the variable head inter? No, the name will be saved in the myname variable. We can say, my weight is equal 92.6, right? So whenever I want to get my age, I can just say my age, and that's it. I will give it to us. Whenever I want to get the name, I say my name and it will give it to us, right? So variables inside the Python will make our life much easier, right? But as you can see, variables can store different kind of value inside them. For example, in here, it's saving a whole number. And in here, it's saving a float number. And in here, you can see, it's just saving a text or a string, right? So this type of coding, it's called dynamic typing, and Python support that. So you don't need to tell it that this variable can save a whole number. You don't need to tell it that this my weight should save a float value. And you don't need to tell Python that this variable can save a string inside it, right? Python will do that for you. But the type of things in Python is really important, and you can get them with type function. Just write type, open parses. And for example, let's just put my H there. And now this function that you can see in here, it will give us the type of Mg variable. And if I head inter, you can see it says it is a int or integer. Integer is for saving the whole numbers, right? So let's just do it for the other one, my name. So put my name in there and wrap it around prances like this, head inter. And now you can see it says the type of it, the class of it is STR, string. No, let's just do it with my weight as well. So a parochy I will put the type there, delete these parts, and now I can put my weight there. And if I had Inter, you can see it says the class of it or type of it is a float. And the good thing about the Python is that whenever we want, we can change the type of things easily. So, for example, right now, my H is integer. It needs a whole number. Can't save float number. But PyTon help us to do that, as well. So if I say my age, right now, it will give us 36. But let's say, I want to say my age is 36.5, right? We can do that in Python. If I had Inter, it won't give us any problem. It will automatically change my age. That was integer to float, so it can save 36.5. So no, if I use type my age, if I head Enter, no, you can see, Python automatically changed the type of my age to float. So in that case, Python is really a smart. 17. 16 Varibales operation: Know that we know about the variables more, let's see how we can use them. So, for example, in here, let me go inside the Python. And in here, what I want to say, for example, A is equal to two, and B is equal to three, right? Now, we can see the result of A plus B, and it is five, right? We can say A is equal, A plus B as well. No A will be five. And B will be three. Okay? So we can do lots more. For example, we can say A is equal A plus A, right? And with that, the A is five, five plus five will be ten. No, A will be ten, right? So if we show the result of A, it will give us ten. And we can say A is equal A plus ten, as well, right? If you show the value, it should be 20. You can see. So with the variables, we can have all the operations. Example, multiplication, division, and all of that. For example, if I say A is equal, A that is 20 divided by B, that right now it is three. Now with that, A is 20, 20/3. What value it will give us? It will give us a float value that is 6.66 6667, right? No, if we get the type of A like this, it is a float. At the beginning, it was just an integer. Now, let me show you some other operations. For example, let's say A is equal to two, and B is equal to three again, right? We can say C is equal A plus B, right? So with this, C will be five because as two B is three, so C equal A plus B will give us five. And no, if we get the type of C, it will give us integer because C is saving an integer. So Python will decide that. Now, again, A is two, right, and we want to say A is equal A, multiply by A. What will happen? A will be four, right? We can do this in a better way. We can use in power of. So we can say A is equal to two. No, A is two, right? We can say A is equal, A, power of two. So to a star, it means in power of two. If I head inter, if I show the value of A, it will be four. And we can do it with numbers more than two, right? We can say B, is equal to B in power of three, for example. No, B will be 27 because B was three, right? So three multiply by itself three times, three multiply by three, it will be nine, nine multiply by three again, it will give us 27, right? So now, we know that we can do operations with variables as well and save them inside another variable. And Python will decide what the variable type should be. No, it's a good time for a cha 18. 17 (Project) Calculate BMI: No, I want to give you a challenge. I want you to calculate the BMI of a person based on the weight and height of that person. You can pause the video in here and go to Google and search for its formula. And I think this is the best way to learn Python because you need to research a lot as a programmer. But let me explain the formula myself. In here, I did search for BMI formula, and you can see the formula in here. It is body mass index. Basically, when we calculated it it will tell us if we are fat or not, right? So BMI is equal weight in kilogram, divided by height in meter in power of two. So we want to do that, right? To calculate the BMI of us, right? So let me give you an example. If you search for calculate your body mass index, you will see something like this. And if you put your height that is 180 mine and my weight is 92.6. In kilogram, if I compute the BMI, it will give us 28.6, right? So we want to create this calculation system, this calculator, right? Pause the video in here, try to do that yourself. We will do it in a second. So for doing that, we need the weight and height. So let's just go here, go inside the Python, and in here, I want to say weight is equal to 2.6, right? And the height is equal to 1.8 because the height should be in meter, so that's why I put height equal 1.8. Now we have two variable. One of them is saving weight, and one of them is saving height. Now we can say BMI is equal to weight divided by height and power of two, right? But in here, everything should works perfectly. But for it to be more readable, I want to use prances, right? So in here, I will wrap this between prances so everybody that want to read or code knows that we want this to happen first, and after that, the rest we want it to happen. Now with that, if we had enter and show the BMI, it will give us 28.58, right? So it's really perfect. This one is calculating the BMI and it will round the top, right? It was 28.58 as we calculated. O code is much more precise than this one. You can see 28 that 58, but this one is says 28.6. If you round this up, it will be 28.6, right? We don't want to round it up. This is good. Now, with that done, you can see if the BMI was 25-29, it means we have overweight. So you can see, I have overweight. That's it. This was our first project to calculate the BMI. And let me put some other values in here. So for example, with up aroky I want to go to weight, and I want to change the weight to 90. And with up arochy, I want to set the height as well to 1.86. So I did decrease the weight and increase the height. Now, I want to use that formula again, head enter with that, and now let's just show the BI, head enter, and now you can see 26. Let's just go and put it in here. 186 with 90 kilograms, right? If I compute, it will be 26. So this one is perfect. No, we wrote a code that can calculate the BMI. No, with that done, I want to do the same inside ID because this is not cool. This is one line execution each time. I don't want to do it like this. I want to create a project for it. Let's see how we can do that. Next. 19. 18 (Project) Calculate BMI python project in vscode: No, we want to do the same inside the IDE. This is the fun part. Let's just open up the visual studio code. We are inside the Python Project folder. And inside this folder, I want to create a new file, and I want to call bmi dot PY. That's it. Now, VS code and Python knows that this is a Python project. So in here, first thing, we want to create a variable, and I want to call it weight. And let's say the weight is 92.6, right? Now, let's just save the height. Height is 1.8. It should be in meter, right? If you remember, if I open this up, can see it is in meter and know with that, you want to calculate the BMI. So we say BMI is equal weight. Divided by open and close prances height, right? Now, you can see the auto complete. You write the first letters, and it will suggest you the height, and you can make a power off two. That's it. Now with that done. We can go to the next line. Now with that, we can show the BMI with a print, right? So put print there and I want to show the BMI and put the BMI there. Now with that, we want to run this code. But before doing that, you can see white circle. It means it's not safe. You can go to file, save or Control or command S on Mac to save it, right? Now, we want to run this code and how we can run it, first of all, I want to use DIR to see what is the file that we have inside the Python project. We have BMI dot PY, right? So we can say PY, BMI and after the head tab, so it will fill it up for you and know if I head Enter, it will give us the value of BMI, and you can see 28.58. So we write the code that can calculate the BMI. And now in here, we can change the values 90, and this one, let's just increase this like before, and no control is to save it. And in here, now we want to run it again up arochy to put the last command there, head Enter, and now you can see again, we calculate the BMI. 20. 19 Create strings: No, we want to talk about strings and using them with print. You see, we did use print in here at the beginning of this course, and we did use print in here. And no, it's good time to talk about it, right? Let me close this one. I want to create a new file and I want to call it strings, and I will add PY at the end of it, right? So in here, there is multiple ways that we can create a string, right? So let's say name, this will be a variable. And for creating a string, I can either use double quotation and put my name there, right. And with that, I can use a print to show that name, just like that. It's safe. No in here, I can say PY strings, tap and it will put it there. No, you can see it showing the string that we put in there, right? No, I want to show you another way of creating a string. If we go down in here on line three, I want to say name two is equal. This time, I want to use quotation marks just like this. And I want to call it David, right? After that, let's just show it. Use a print to show the name two, that's it with the autocomplete is really easy, right? No, before running it, head control is to save it, make sure you are saving it. After that, we say PY, strings or we can use up arrow key to put PY strings PY there, head Enter. And now you can see first, it will say Navid this one, first one. After that, it will say David, the next one. Next thing that we can do in here, we can use double quotation and quotation mark together. For example, let's say M string. You can see the S is big. This uppercase and lowercase in the name is really important. Just remember that I want to say my string is equal to a double quotation string. We want to say he Navid, right? Just like that. So you can see I did use quotation mark inside double quotation marks, and that is why we have two type of creating strings. So we can use the double quotation and quotation mark inside the string as well. So in here, Python knows that all of these are just a string, right? Whatever that is inside of it is a string. Let's just show this only use print my string, right. And with that, if we use Control to save it and in here of Aoki at Inter, no, you can see we can print the cutan march as well. No, this can create some problem. Let me copy and paste all of these in here as well. This is M string two. In here, if we put double quotation in middle of these two double quotation, make sure you save and go here and run the program, it will give us an error because when we start a string with double quotation, whenever Python see another double quotation after that, it assumes that your string is finished. It is that, right? So you can't do this kind of stuff. If you want to use, for example, double quotation, inside a string. How you can do it. We can just delete this. Use a quotation mark like this. We can say Navi has double ctation like this gun, right? That's it. So we are using double quotation, and Python knows because this string is a start with cuation marks. I will assume whatever is between the first quotation mark, and the next utation mark is a string. Doesn't matter what it is, unless it is another utation mark. And now with that we want to show Myastring two. So let's just put MyString two in here. Head control has to save it. And in here, let's just run PY strings PY head inter, and now you can see it says NawT has double quotation gone. It has a space at here, Y because we have a space in here. So if you delete that, head control is to save it and run over code again, you can see it says Navit has gone. You can see now, you know how you can create a 21. 20 String indexing: No, next thing I want to talk about strings more. What I want to do I want to create a new file and I want to call it strings. Two dot py, right? So with this in here, I want to create a string. You know how to do it. I want to call it my string. Just remember, uppercase and lowercase in the name is really important. I want to equal it to a string that it says hello word inside it, right? Make sure you save always. Now in here, let's say we want to get a one of these letters, for example, letters on location of four, for example, right? So this H is on location zero inside this screen. This is the location one. This is location two. This is location three, and this is location four. So if you want to get the location four of this string, that is O, we can say M string and square bracket. And in here, we want to say, give me the letter number four. And we know that letters in a string is start from zero. So zero, one, two, three, four. So this should give us O on output. Let's just save it inside the variable. I want to call it A, for example, right? And now, let's just show this A. I want to say print A. That's it. Control A to save. And knowing here I want to use up arrow key strings two after that head tab. And now if you run it, you can see it'll give us O on out foot. So that's good, right? But getting just one letter is not helping us a lot. Of course, at some point, we need to do that, but I want to show you more cool stuff with this. I don't want to put these things inside another variable, what we can do. We can just delete this and put this M string number four directly in here. Just like that, if I had control is, what will happen if you run, it will give us the same result. We did use less variables. It's just that, less variable, right? Now, let's say we want to get this W, right? How we can get it, we can say zero, one, two, three, four, five, six. So if I copy and paste this printer string down here and tell it to give me the index six of this string, let's see what will happen. Control is to save and in here up arochy at Enter, and now you can see this giving us W. No next thing, let's say we want just the word part of this string. How we can do that. For doing that, there is a way. We can say print Okay. And in here, we can say M string again, use square brackets to get something off of it. But this time, I want to say from this W that is index six. And after that to the end, give me all the characters. How we can do that, we can use Colin to do that. So from the left side of this column, we want to tell it to start from a index and show it to me to the index that we put on the right side of it. So, for example, the W is at index six. So we can put six in here. And for the out foot, you can see it is D, right, six, seven, eight, nine, ten. So you May 10, and it should be that, right? From index six to ten, show me the letters in our string, right? So let's see what will happen. If I use Controls to save it and in here, run, you can see, it's just showing world. It's not showing the D. Why? Because this angle bracket, what it is doing, it is not getting that last letter that you put in. It will end at a letter before that. So if you want to have D, we should put 11 in here, right? So it will start from index six to ten, and it will show it to us. Control has to save, and knowing here if I run again, you can see it will give us word, and that's how a string indexing is working. Another way to do this, we can use Control C, put it over here, Control, and in here, we can say, from six to the end, show me everything. So we don't need to put this 11. It will put the max index number there automatically, just like that. It will start from index six and it will show everything after that doesn't matter what is after that. So let's just use Control S and in here, run, and you can see it showing us word. So you don't need to specify the last letter if you want to show to the end, right? So, for example, if I in here, say, from course and again, use Control S to save and after that run, what will happen? Te print my String six to 11. Again, it's printing word, but this print the S string from six to after that to the end, it will print word from course. Can see we can do it backward, as well. So let me copy and paste this one more time. This time, let's just say we want to get the hello, right? One way is to go from zero to index five. So zero, one, two, three, four, and we should add one more to it at the end, so it will put the O and output as well. So with that, control is to save in here, let's just run. You can see it is giving us the hello. But again, for zero, because it is the start of or a string, we don't need to put it there. So if I use this printer string down here, and tell it whatever comes before index five, show it to us. Again, it should play the hello for us. Control us to save, and in here, run, you can see, again, it's showing hello for us, right, cool. So these were some ways that we can take some part of a string and show it in output. Another thing that we can do in here, we can copy and paste this. Let me show you a trick. If we don't put anything for a start and end index to show what it fill do, it will give us the whole string. I assume from index zero to the end, right? When you don't put anything there at the left side, it's put in zero there automatically. And for the right side of this hold, it will put the last index there. Now with that done. If you use Control S to save it and runaway code, you can see it says hello word from course. So it will show everything for us. No. Next thing that sometimes you may see is that we have something like this. Let me use this. You can see. We have double colon, right? If we do something like this, again, if you run over a game, you can see it will print everything normally, right? But why we have two colon? For you to see the difference, what I want to do print I want to use a string with some dots in here, and know if I had Control S and in here run, you can see from these dots, we are putting some new codes to explain some new things. So you know all of this is for all of this, and this is for this one, right? Now let's see how we can use double colon, why we need them. So first first, with double colon, let's just say we want to get the word. So we did it like this, print my S string from index six to 11, okay? Index six to 11 11 that is in here, right? We can do the same in here. Start 6-11 and don't put anything there at the right side of this last column and save and in here, run or code. Again, you can see it will give us what exactly like before, right? And everything that you can do in here, you can do it in here as well. Everything. But this last place that we have in here is for step size, right? So let me show you an example. Copy and paste. What I want to do, I want to say the whole string. So at the left side of first column, and at the right side of it, I won't put anything. So this will give us all the string, right? But at these step size, I want to say two. Now, let's see what will happen. Control is to save run again, you can see what it is doing. It will get all of our strings and the step sizes that it takes to grab the letters, it is two. So for example, first, it will print the first index. After that, it will go to Index two. After that, it will go to index four. After that, it will go to Index six. After that, it will go to index eight. So the step size is two. Each time the index will be increased by two and it will show that letter to us. That's what is happening in here. HLO word you can read it, right? So this is for step sizing. So with this, we know that the first colon in here is exactly this column that we have at top here. But the next column at the right side of it, we are deciding the step size that this string should go and grab the letters, right? And that's it. Now you know about double column inside a string index. 22. 21 String operations: No, I want to show you how you can add strings together. Let's see how we can do that. For doing that, I want to create a new file, and I want to call it strings. Three dot PY. And that's it. Now, in here, I want to create a string. I want to call it my SDR, and I want to put hello there, right? Now with that done. First, let's just show it. Print my SDR. That's it. Now with that done. Let's just run PY. Strings three dot PY. Now if you run it, it will say just hello. But we can add things together. I want to say my SDR two, is equal my SR plus my SR again, right? Now, let's show that with a print. This time we want to print MSDR two. Let's see what will happen. In here, if I run you can see it will add them together. Hello. And after that, hello, it will add them together. No, we can do more. Let me copy and paste this down here, what I want to do this time, I want to say my string tree, my STR or string tree for both of these. No, this time, I want to add a space between these two hello. How we can do that, we can add a plus in here and create a string between them within a space. So what will happen? It will say hello. It will add it to this empty space, a string, and after that, it will add hello again. With that, control S to save and no let's just run. You can see, no, between hello and hello, there is a space. No. Let's just give you another example. In here, we want to say hello word. So we can just delete this. And inside this, I want to create a string. I can say Wort, right? We don't need this space, so let's just get rid of that. My STR is hello, and we create a string in here that you say Wort. No, I want to change the name of this to four and in here four, so we can show it. Control is to save. No, in here, let's just run. You can see it says hello word. No, we want to add a space between hello and word. You can see I can add a space in here and control is to save. Now, in here, if I run, you can see it says hello word, right? No, MSTR four is hello word, right? Let's just add to it. For example, I can just say print. And inside this print, I want to say MSTR four plus. We want to add a string to it inside these princes. We can do that, right? I want to say space after that from course. That set control is to save. Now in here, if I run, you can see, at the end, it should say hello word from course. No, we did use adding a string together, right? We have multiplication as well. So let's just say MSTR five is equal to a string N, right? So what will happen if we multiply this by a number? So for example, let's just say print. And inside that, you want to say MSTR five, multiply by five. What will happen, it will print MSTR 55 times. So it will have five N after each other, right? Control S to save and in here stron you can see it will print N five time. So you can see, we can add strings together. We can multiply strings with the number as well, right? But let's say we want to do something like this. We want to say print. A string doesn't matter what, which one you want to use plus a number, right? Let's see what will happen. We are adding integer two, not a string two, right? So in here, if I run it, you can see it'll give us an error. So you can add strings together. You can multiply strings by integer. But you can't add a string to a number. Float number or integer number doesn't matter. You can't do that. It will give you an error. If you want to add two, at the end of the string, you can wrap it around double quotation or single quotation, right? Save and know if I run, you can see it will say N two, because we add this myString five that is N, a string of N, and we have a string of two, so it can add it together. Know you know about how you can add a string together and multiply them what you can do and what you can't. 23. 22 Method and documentation: To this point, we did work with the strings a lot, but I want to show you another thing. So in here, let me create another one, and I want to call it strings four dot PY, right? And in here, I want to create a string. Let's just say my STR is equal. Hello word, right? Now with that, this string variable has some methods on it. It has some functions that you can use with it, right? So for example, if I write my STR and put dot after that, you can see it will show us a lot of functions. And whenever you see some box like this, with this color, it means it is a function or method that we can use on it. For example, if I want this string to be in upper case, we can say upper, and it is a function. So we should add open and close parentheses. Know what this will do. It will take this string and make all the letters uppercase. So for showing you that, I want to use a print, open and close parents and with that, I want to cut this with control and control V to paste it over here. Now, if I save in here, go to right pie strings. Four and head tab, you can see put it there. I I run, you can see the hello word no is in uppercase. If you want it in lowercase, again, let me copy this, paste it over here. And in here instead of upper, we can say lower, right? Again, because it is a method or function. It needs a open and close prances. Now with that, if you run, first, you can see it will write it in uppercase and after that, it will write it in lowercase. If I change one of these two uppercase, for example, this L in here and run or code again, you can see, again, it will put it in lowercase. So this uppercase, lowercase, doesn't care if one of these are in uppercase, one of them in lowercase, it will change whatever that is uppercase to lower case in this case, and this one we'll change whatever letter that is lowercase, it will make it uppercase, right? No, another thing. Let me paste it one more time this time. I want to capitalize it, right? Capitalize. That's it. If you want to see what this can do, you can hover over it, and it show you a version of documentation that it says, return a capitalized version of this string. More specifically, make the first character have uppercase and the rest lowercase. So let's see what will happen. If in here run, you can see the hello word, the first letter it's in uppercase, and the rest is in the lowercase. So we have lots of functions, and if you hover over them, it will tell us what they are. But there is other ways to read through documentation. And I don't want to limit you to this course or any other course. Maybe in future, there is Python four, Python five, and you want to learn them as well. And how you want to learn them. One way is with course, but when you get to be a professional, you don't have time to go through courses. So what you do, you go to documentation. So if you go into the Google, search for Python you can find the page of Python and you can open up the documentation there. So open up documentation. You will see something like this, or you can just click on documentation after that Doc. And in here, I can click on the Python Docs, and it will open up the documentation in here. There is a lot of things in here, but the best way and easiest way to find things that you want is in library references. So with the middle most, I will click on it to open it over here. Now in here, I want to check what these MSDR or String can offer us like this upper, lower capitalize, right? So what I want to do I want to use a type function, right, and put the MSTR there to see what is the type of this string, right? And I want to show this type with a print with open closed prances like this. And know if I run, you can see it says it is STR or a string. So we can go here in Python Standard Library, head Control F to search for SDR. Now go down. You can see text sequence type STR. No, let's just open that. Now, this is a documentation for the SDR or a string or this that we create over here, right, that we use upper, lower capitalize on it, right? Now, in here, if you go down, you can see there is a string methods in here that you can see they capitalize in here, and it will tell you what they are, and it will tell you if they change in other version as well. We have as fold full documentation in here. We have center, count, encode, ends with expandabFin cool format. We will talk about this format as well. If we go down, you can see there is a lot of them. Doesn't matter how many course you want to take, you need to be familiar with the documentation. That's why from now on, I try my best to show you the documentation. So you can work with documentation. So in future, if you want to do something new that none other course is teaching you, you can find it inside documentation. 24. 23 Format string method: If you remember, we did calculate the BMI, right in here. But we were just showing a number, right? Know what I want to do. I want to show it with some other text so it will be more professional, right? We are making our BMI project much better every video. So let's just do that. In here, I want to copy all of this code for calculating the BMI, and in here, I want to create a new file and I want to call it format. String dot PY, right? And here, I want to paste the code. Now I want to show the BMI in a better way. And how I can do that, I can say print. BMI is, right? We want to say BMI is this number that we have in here, right? But how we can do that? Can we just say plus BMI? Can we do that or not? Let's see. If I say Pi formatted string head inter, you can see it will give us error because we can't add a float or any number to a string. We need to first convert this BMI to a string, and after that, added to this BMI is a string, right? So for doing that, we can use a function that is called STR. This STR function can convert whatever you put in there to a string. So if you put BMI there, no, let's see what will happen. In here, if I run the code again, you can see it says BMI is 26, but we need a space in here, so we can just add a space in here, know if it's safe. We can run it, and now you can see BMI is 26. You can see the difference. From before, we were just showing a number, but right now we are telling it what it is. And this is not the only way that we can do it. There is better ways as well. For example, if we go to documentation, we have a method for strings that is called format. And with this format, we can inject numbers and whatever we want inside a string, much easier, much more readable. So let's just go here on a say print. This time, again, I want to say BMI is open and close curly braces, right? This is a string that has open and close curly braces, and with that, we can format it. Just a dot after that and write format. And this is another method that you can see it in documentation. You can see how they did use it. I will explain it completely. Don't worry about it. You don't need to go to documentation. For this one, if you forget it in future, you can go to documentation, and it will be much easier to understand it after watching this course, right? Now, what will happen? This format method search through the string. And it will replace the curly braces by whatever we put inside these parentheses, for example, BMI, right? Control is to save. Now, in here, if I run, you can see again, it says BMI is 26. So either you can use this version or this version, there is other versions as well, but you can use both of them. This way is much cleaner and more beautiful and more professional. Now that we know the basic stuff about the format method, let me explain it more and give you lots of tips in next. 25. 24 Format string tips: Now let's see what other things we can do with this format method. I want to copy and paste this what I want to do. I want to show the height and weight as well. So in here, I will say weight is equal to open and close curly braces. And height is equal to open and close curly braces, and BMI is open and close curly braces, right? Now what will happen. How we can replace all of these curly braces with this format. We have just one in here, but no in here, format will check the string from left to right. First curly braces that it see, it will replace it with the first input in here. For example, wait. That's it. I didn't write this correctly, so let's just put it there. No, again, it will go to right and when it see the next curly braces, it will replace it with the next input inside it. So let's just put height in there, right? And again, it will go to right, and when it see the next curly braces, again, it will replace it by its next input, that is or BMI, right? That's it. No, it's just save and go here and run it. You can see weight is 90 height is 1.86. BMI is this. Now you can see it looks more beautiful, right? It's not just this to check from left to right, first curly braces replaced by first input, second curly braces. Replaced by second input, third curly braces, replaced by third input. There is other ways as well. So in here, let me copy and paste it. We can give them indexes. For example, we want to say, this is the first index. This is the one index. This is two index, right? So what we are telling it to do with this is that replace these curly braces with the input zero. That is this one. Replace these curly braces that has one inside with the input index one in the second input, right? And replace these curly braces that has two it with the zero, one, two variable inside, zero, one, two, input. Okay? No, this will exactly work like before. Let me run it and you can see exactly like before. Now, let me give you another example so you will understand this better, copy and paste it over here. If I put all of these to zero, what will happen? This format will replace all of the curly braces that has zero inside it with the weight, right? Because this is the input zero. So now if we save and run what will happen, it says, weight 90, height, 90, BMI is 90, right? So you can see how it works. We can give it numbers and we can do it however we want. Let me copy and paste it one more time. We can say this is two, this is zero, and this is one. Now what will happen. It will replace these curly braces that has two inside with the input two with VMI, right? Next, it will replace these curly braces that has zero inside with the weight that is input zero, and it will replace these curly braces with the number of one inside with the input one that is over height. Now, let's just save that and run it. You can see weight is 26, height is 90, and BMI is 1.86. You can see how you can work with it. It's not just this. There is other ways as well. Let me copy and paste this one more time. The format give us a lot of options. So for example, in here, I can change this to W. I can change this to I can change this to B, right? So what will happen? No format, how does it know which one should be replaced with which input, right? For format to know that, we can do it like this. W is equal to weight. H is equal to height, and this one B is equal to BMI. So what will happen? Format will replace these curly braces with the W. W is over weight, so it will replace this with this weight. Again, for the height, it will do the same. So it will replace these curly braces with H inside it with this height because H is equal to height, and so on. So let's just save and run it again. You can see exactly precise, right? You can see in here, we did replace some integer. We did replace some float value, and again, some float value. It's not just that. We can use whatever type of variable that you want in here. And this format will convert it to a sring and it will replace these curly braces with it. So for example, let me in here. Create a variable and call it name. Name is equal, David, for example, right? And know it that we can go down in here and I can add some string. You can see how easy we can do that. We can say name is equal to open and close curly braces and the rest, right? And in here, I can just put N in there, right for the name. And at the end or at the beginning, doesn't matter where you are to do it because you reference it with a letter. No, in here, I can say N is equal to name, right? This name is a string, and again, it should work. Let's see. I did use Control S to save. Now, let's just run. You can see name is David, weight, height, and BMI. You can see how easy you can use format to put a string, float, integer, and all of that inside a string and show it. And you can do the exact same thing that we did in here with these numbers as well, right? So let me copy this. Control C to copy it and paste it over here. No, we want to add this name. We can just copy it like this from here to here. But instead of giving it a letter, we want to use numbers. So three, right? So this time, the priority of these inputs is important because we did use numbers for referencing curly races, right? So this time, we need to put the name at the end at input three because we put three in here, right? Now, with that, if we hit Control S and Runo game, you can see name Na weight, 90 and everything is working fine. But another thing in here, we could just put this an equal name to middle to the beginning to wherever you put it, it will be okay. But when you use numbers, you need to be careful about where you are putting your inputs inside this format. And that's it. Now you know everything about formatting a 26. 25 Format with fstring: No, I want to show you a newer method of formatting a string. Let me show it to you. I think you would love this because it's more cleaner than this one. What I want to do, I want to get all of these for calculating the BMI and the name and everything, right, and create a new file and I want to call it format string two dot PY. And knowing here, I want to paste that code with Control V. Knowing here, we want to show the BMI. So we can just say print, right? You know lots of methods. No, I want to show you a new method. You say F and after that, to double quotation, and know inside this double quotation, you can say BMI is this time open and close curly mbaces and inside that, we can say BMI. That's it. Beautiful, right? Yeah, that's cool. Now, let's just run it to see if it's working. Um, I want to say PY format string two, right, and Shron. You can see BMI is 26. So you can see this is working fine. Why I teach the old way because if you go inside a company and you are part of a team, they have all their code as well. So that's why you need to know about all of these things that we have done in here so you can work with them, work with your teammate, right? So that's why I did teach those, but this is good as well. No, we can do lots of things with this, right? We can say F double quotation mark and knowing here, we can say name is equal curibrass and inside that name, right. After that, we can say weight equal weight, right? After that, we can say height is equal to curibrass height. And after that, we can say BMI is equal curbrass BMI, right? That's beautiful. You can see how clean it is. So in here, if I run, you can see name is David, weight, height, and BMI. Everything looks perfect, right? I suggest using this, but the older way you need to know about them as well. Even this one, you need to know about them as well. There is lots of code in Internet, even from big companies that are using the method as well. So you need to know about everything. That's it. Beautiful, clean, readable. 27. 26 Create list: No it's time to talk about the lists. What is a list? We did work with it before, but you may didn't know. So for doing that, let me create a new Python file, and I want to call it List one and PY dot PY, right? So in here, we did say my STR, a string of hello word, right? And with this, what we have done, we did get some number of it, right? Like this, we say, for example, give me the right? And we did show it with the print. So let me wrap it around a print in here. And with that, let me run it. No, you can see it did give us And if you put one in there, it will give us E, right? So let's just save and Run, you can see, did give us E. This is called string, but in other words, we can call it list of letters. That's it. List of letters. Cool, right? So we did work with list of letters, but there is a specific variable type that is called list. So let's see how we can create a list. I want to say my list is equal, for example, one, two, three, right? So this is a list of numbers. This is a list of letters or list of characters, and this is list of numbers. And like we get one of these characters and show it with this print, we can do it in here as well. We can say, My list, right, and we want to get the index zero of it. Index zero is this one in here, right? That's it. No, let's just show that. If you run, you can see it give us one in here. Cool, right? So it is exactly like a string, but we can have things in it. So, for example, let's just say my list two is equal. For example, at the first point, we want to say 1.6, and for the other one, let's just say a string, right? Let's just say David. Next, we can add whatever we want. For example, ten, an integer value, and after that, another string like Hello, right? We can do lots of things with it. We can save lots of things inside this list, right? So we can go here, print one of them. Like, let's just say my list two of these, my list two, the number one. It is a start from zero, one, two, three, right? So if you put one in there, it will give us the David, right? So let's just run and you can see it, give us David. If you put two in there, zero, one, two, it will give us ten. Let's just save and after that run, and you can see it give us ten. So a list can save whatever you want inside it, and you can get them and change them as well. So for example, in here, I can save my list two, and in here, we can say, change the David that is index one, 01, right? Change it to, for example, max, right? So Max or whatever, right? No, if we show the value on that position, let me go here and tell it to show us Index one, 01, that we change it to max. Let's see what will happen. So you can see, we did change the value inside it. It's not just you can change a string to a string or float to a float or whatever. Let me do something. In here, I want to say print, and in here, let's just say my list too. Just with that, let's just see what it will show it to us. You can see it will show us the whole list for us so we can see what is inside it. So this is cool tricks that we can learn the lists, right? So, no, we did change the David to Max, right? No, we can change it to a number. Let's see how we can do that. We can say my list. Two, change the index one, that right now it is max. We want to change it to numbers like 100, right? Why not? No, let's just run and show that. You can see it is 1.6 after that 100, after that ten, after that hello, you can see, we can change things inside a list. We can take things from the list and use them, and we can manipulate items that is in the list, right? Now, you know how you can create a list, but I want to give you lots of tips and tricks. 28. 27 List slicing: Now let's just talk about the list more. For doing that, I want to right click on this one. I want to say close others, so we have a clean slate in here. Now, I want to create a new file and I want to call it last two dot PY, right? Now with that, what I want to do I want to create a list. I will call it my list is equal. Let's just say one, two, three. That's it. Just like that, we have a list. At the end, let's just show it, right? Print. And I want to show the list, my list, right? Now with that done, let's just see how we can run it, my list two. And now you can see it's just showing us one, two, three. Now, let's just say we want to add something to this list. How we can do it? We can say my list, add another list. So this square brackets that we have in here, it's representation of a list. So we can add four to it. List that has just one input inside it and it's four. Now let's see what will happen if we run it. You can see I did run it, and again, it's not added there. Why it's not added there? Because these kind of things when you do it, you need to save it inside itself as well, so it will happen. So for doing that, we should say my list is equal my list that has one, two, three inside it plus four, right? Just like that. No, if you run or code, you can see, no four is in there, right? One, two, three, four. And it's not just like that. We can add more to it. For example, in here, I can say, my list is equal, my list. Okay, you want to add more to it. Let's just say we want to add a string, David, right? After that, I want to add another value like 5.6 a float value, right? That's it. Let's just test that, no. If you run, no, you can see the David is added, and 5.6 is added to it as well. Now with this list that we have in here that has one, two, three, four, David, 5.6 in it, we can do lots of things that we did with strings. We can do it for this, as well. So, for example, you can see this list is started from zero, one, two, three, four, five. Let's just say we want some part of this list from index tree. How we can do it? We can say my list, give me with this call and we did it for a string. We want to say zero, one, two, three, from index tree to the end give the list to me. And I want to show that with a print like this, print it out, right? It won't change the list at all. Now with that, if you run, you can see from four David 5.6, we get it and we did show it. Of course, again, it's not changing the list at all. If I print it again in here, you can see it's not changing it at all. If I run, you can see it is exactly the same as before. We did get some part of it to use it, right? We didn't change it. If you want to change a list, you should say it is equal to that, right? Now, let's just delete this. What else we can do? We can do whatever we did with the string in here as well. So we can say my list. For example, we want to say with the sullen that whatever that comes before David, show it to me, right? So zero, one, two, three, and four is David. So we put four in there, so it will get the four, three, two, one. It will get it and it will give it to us, right? And it will show it. Let's just run, and now you can see it just gave us one, two, three, four. No, let's just say we want to get the David and four. How we can do that. We did it with strings as well. We say, my list. And with Colin, we can do that. So, for example, in here, we want to get the four and David, right? So zero, one, two, three. So the start point should be three at the left side of Colin. And at the end because we want to get the it is zero, one, two, three, four and five, because when we put five, it will start 4-1 index before that index that we put at the right side of this column. So if you put five in there, what will happen, it will give us David and four. So let's just see if it's working fine or not. Run and now you can see. It did give us four and David. Now, you can see how easy we can do things in the list like we did for a strings as well. 29. 28 List methods: Now let's just talk about the lists more. I want to show you some method for the list. For doing that, I want to create another file. I want to call it list three dot PY, right? And in here, what I want to do, I want to create a list. I will call it my list. Is equal, let's just say one, two, three, right? Now, with that done, I want to see the type of it. If you hover over it, it will tell you a list of end. So this list is important, right? So let's just go to documentation, go to library references, and in here, head Control F to search for list, right? Go down until you see the list, and you can see sequence type list topple range. Just the list we want. So click in here and know in here if you go down, you can see there is lots of things that we have in here. I will explain the most important one, like how we can create a list, how we can sort things out. And let me go up, I think here in here, can see how you can change things. You can append, clear, copy, extend, pop and remove reverse, all of that, right? So in the documentation, you can see, there is lots of things to learn. You can see how big it is. I will show you the most important ones. Now, in here, we have a list, right? We want to add to it. In last video, I did show you how you can add to this list by adding a plus, right? There is other ways. So we say my list dot append, right? And this append is just a method or function. So that's why it need open and closed parenthesis. And in here, let's just say we want to add four to this list. After that, you want to show it. So with the print, I want to show the M list. That's it. No, control is to save, and in here, let's just run it. Pi is three and head inter. You can see with the append with it at one element, one item at the end of our list, right? We can do more. So for example, in here, I can say my list dot append, right? It is a method, so it needs open and close parenths, and I want to add a string, for example, David, right? Control is to save. And after that, I want to show it one more time over here. No, let's just run in here. You can see No, the David is added to our list. So with the append, we can add the stuff, right? There is other things as built. So, for example, let's just create another list, and I will call it my list two. It's equal to the five, three, eight, two, one, four, six and seven. You can see this is a list of numbers that it's randomly placed, right? There is a method inside list class that it will allow us to sort it out. So with the sort method, that's we can sort these kind of things. So print. And in here, we can show thee my list too. Now, let's see what will happen. If you run, you can see O numbers in our list is randomly placed. But with this sort method or function, it did sort it out. One, two, three, four, five, six, seven, eight, right? We can do the same with the letters as well. So for example, in here, if I say, I want to randomly put some letters there. For example, this one, I want it to be A, right? This one I want it to be B. This one I want it to be C. This one, I want it to be F, this one, I want it to be L or whatever, right? This one to be G, and this one, just put J. This one, just deleted at M, right? So we randomly put some characters inside this list, and let me change the name of the list to list three, so you have all of them, always. Now with tatonT sort, we'll sort this out correctly based on alphabet, right? So let's just run. And now you can see ABC FGJLM and you can see it did sort it out. So this was for sorting. Next, let's just say we have a list. Let's just call it my list four, and it has some names, David, Max, and let's just put some numbers there like 2.6, 8.9, and some big value like this and like this, right? So we have some integers, some floats, some text, right inside this list. And what we want to do, we want to be able to delete some of them. How we can do that. We can say, my list four dot POP Okay. What this pop two, it will delete one item at the time from the list, and it will give it to us and we can save it somewhere. So in here, let's say we want to delete the max. So Max is zero, one index one, so put one in there. And what this will do, it will give us a value on output like this and we can save it somewhere. We can call it popped item is equal to the item that we popped that is max, right so in here, I want to use a print to show it. And for doing that, as an exercise, I want to use a string. So in here, we say Last is my Last four, right? And we popped open and close curly braces. We say and we popped popped item, and that's it. I think that looks beautiful. Now, if you run or code, you can see it says List is David, 2.6, 8.9 and this, and we popped Max off of it, right? You can see how beautiful it is to use print FS strings and how we can pop something up. As you can see in here, in this list, we don't have Max anymore because we did pop it off, right? Ooh. No, we know how we can add to our list, sort our list, and delete from our list. I want all my examples to be practical. I don't want to overwhelm you with lots of information. As you can see till now, I did teach you integer, float, strings, and know the list. I don't want to show you all the variables that we have in there and all the methods because it's too much for you and it will be boring. That's why I'm using a practical examples to show them to. So that was about some important list methods. 30. 29 Create dictionary: The next variable type that I want to talk about is called dictionary. So let's just go inside the VS code in here. What I want to do, I want to close everything and in here, create a new file and I want to call it dict dot py. Dig one, right? Now, in here, first, let's see how we can create a dictionary. It's like a list, but instead of just an index that is a number, we can give any value that is inside that dictionary. A key. So with that key, we can get the value. Let me give you an example. I will say my dict, right, is equal for creating a dictionary, we need open and close curly braces. And first, we need to specify the key, for example, in here. I want to say key one and for the value that this key represent, we add Colin and we put the value there. For example, we can say 100, right? This is or value. And this is our key. So whenever we want to get this value, we use this key to get it, right? Let's just add more, and we will talk about how we can get them as well. The key should be a string. So in here, create a string either with double quotation or single quotation, doesn't matter. For example, in here, I want to say key two. You can name it whatever you want. Doesn't need to be key, right? Whatever string. And the value that it is representing, let's just this time use a float value 10.6, right? And let's just add another one. This time, I want to use single quotation and I want to say P three. And in here, the value that it is representing, I want to use a string, for example, David, right? Just like that, first, let's just show it with a print midt, right? That's it. No, let's just run it. We say PY. In Linux and Mac, you should say Python three, right? In here, we say PY, dit, right? Head inter. No, you can see, there is a key value pair in here. Now, in here, let's just see how we can get a value from this dictionary. For doing that, I will say my dit and like a list. Again, we need this square bracket, and we can tell it to which value I need, right? For example, if I want the 100, we pass K one. If we want this value, we pass two, and if we want the David text, we can pass three. So in here, the way that we want to get things is with a string. So for example, in here, I want to get the key two, for example. So we put the key two string in there and know it will return the 10.6 for us, right? And we can save it inside somewhere. Let's say, for example, A equal to this. No, with that, we can print A, right? Print, A, that's it. Let's see what it is giving us. If we run, no, you can see it will give us 10.6. And for you to see it better because we know about FS strings, we can say F, doll quotation in here, and we can say A is equal to curly braces. A, that's it easy, right? Now with that, you can understand it better. Let's just run. No, you can see, A is 10.6. We get it from a dictionary that its key is called key two, right? That's it. No, we did create a dictionary and we use it, right? Let me give you more example in next. 31. 30 dictionary practical example: So now, let's just have a practical example of dictionary. So in here for that, I want to create a new Python fall. I will call it dict two dot PY, right? And in here, I want to create a dictionary. And this time, I want to call it David dit, right? David dit. So we want to save all the information about David inside a dictionary, right? So we say equal to curry braces. And in here first key, I want to save the name, right? So the key will be name and the value, I wanted to save the name is David, right? So put David there. Next, we want to store the weight. So in here, again, the key should be a string. So we say weight, and the value of this key that is weight is, let's just say 90. And next, let's just store its height, right? Again, we need the key. The key. If it is height, it will be more readable, right? So in here, the value that this height represent, we want to say 1.86, right? That's it. Now, we have a dictionary for David, and we can use that dictionary. For example, let's just say print, David. Dictionary, and we want to get the name of David. That's it. We get it like this, right? And if we run dig two, let me go to dig two, and you can see it give us David, right? Cool. Now, let's just get the weight of David. So in here, just change the key in here to weight and pass it there. Or you can just copy it from here, Control C to copy it and control V to paste it over here. Now, again, we can take this, copy it and paste it over here. This time we want to show the height of David, so we can put the height in here, Control S to save, and know in here, I can run it and you can see it will show us the name, the weight, and its height. So you can see how readable it is. Dictionaries is really good for readability, because everything in here is self explanatory. 32. 31 Dictionary tips: No, I want to talk more about dictionaries. So in here, I want to create another file, I will call it dit t dot PY, right? And in here first, let me create a dictionary. My dit, right, is equal to. Let's just say the first key I want it to be name. And the value that it represents, let's just say, David, a text or a string of David. And after that, I want to save the things that David bought, right, bought on a store, right? So, for example, in here, we can give it a key items bought, right? This is the key, and for its value, we can use list, right? That looks awesome. So in here, we can give it a list. So, David, the item that he bought is this. For example, we can add a mouse after that, you know the list how it works. He bought a keyboard, right, put some things there. He bought a monitor, so put monitor there, and that's it. You know how list works. We can put float value in there. We can put integer value, string value there, and we can do it for the dictionary, as well. So in here, for example, at the next key pair value, I want to say the price of all, right? So in here, I need a key. You can say total price, right? And for the value, let's just say $500 for all of them, right? So now, we have a dictionary that is saving a string that can save a list, and that can save numbers as well. So no, let's just see how we can get them. We did get a string. Let's just see the total price. Oh, I can do it. I want to use a print. And in here, I want to use a string. To show it, right? We want to say, David spent $500 in a store, right? So for doing that, we can say, first, get the name with curly braces and say my digged, right, and we want to get a value inside it. We want to get the name first. So what will happen first, it will print out the name. And after that, we say pint for example, $500. And how we can get this $500, again, a curly braces and inside it, we say, M died and we want to get the total price. So in here, we add a square bracket to get the total price. And now let's just run the dig tree like this. And now you can see it is say, David spent 500. So if we change things in here, for example, let's just 700 and David is Max, right? If we do that and run over code, you can see Max has spent 700. Now, we can add more to this. After saying that it has spent 700, we can say D item that was butt W. So again, we need a curly braces, and we want to get my dictionary item butts so it will give us all the items in here, the list, right? So in here, we can say, My dit, give me the items bought. That's it. Now, let's see what will happen with that. We run, you can see Max spent 700. And the item that was bought was mouse, keyboard, and monitor, right? Next thing that we can do, we can get this list element one by one if we wanted to, right? So for getting one of them, say for example, my dig, right, and we want to get these item bots. So we get the item bots in here. We put the strings, item bot either with copying this or auto complete, right? And what this will give us, it will give us this list, and we can save it inside the variable. For example, items, right? Whatever name that you want to put in there. Now, let's just print the item, print item. Items, right? Now, let's just run. And now you can see it is showing us the items, mouse keyboard and monitor. Let's just say we want to get the first item that we bought. How we can do it because this item is just a list because you see it is a list. We can get items off of it. So we can say like this, give me the item in index zero, right? So just like that, control is to save. And now if we run it, you can see it will give us mouse in here. If you put one in here, it will give us keyboard. Make sure you save before run no, you can see it is giving us keyword that is professional and beautiful and readable, right? You don't need to save the list that you get from a dictionary to show it in a print. The easiest way is to get this my dictionary like we did it over here. And like this, we know that the dictionary for item boot will give us a list, so we can get a list item from it, right? So like this, we can say zero. Give me the items bought value that is inside the dictionary, that is a list. So we know that this will give us a list. We need the index zero of it that is over most. So with this, it works as well. If we run, again, you can see it is giving us mouse. So you can do both, but for it to be readable and easy to develop in future, it's better to stick with this version. So just save the list that is inside a dictionary, inside a variable, and after that, use that variable, right. This way is much cleaner to do things, and it's easier for team works. So now, let's just save, and in here, run, and you can see it is giving us mouse. 33. 32 Dictionary operations and methods: I want to show you how you can edit a dictionary and add to it. So for doing that, I want to create a new file. I will call it digT four dot PY, right? And in here, I want to create a dictionary. So my digT and equal to a dictionary. First key, let's just say name and the value that is representing let's just say David, right. And after that, another key, let's just say weight and the value that it's representing, it's 90 integer value. And that's it. That is our dictionary. First of all, let's see how we can add to this dictionary and add height to it. Right now, if you print, let's see what will happen. My digged right? And we want to run it. We say PY digged four, that's it. Now, you can see there is just name and weight, right? We want to add the height to it. So we can say, M died in here, we add or key. The new key, for example, let's just put inger and we want to say it is equal to 1.86, right? After that, let's just show the dictionary. By a print, my dict. Now, let's see what will happen. If it run, you can see, No, the height is added to it. Cool, right? Now, let's see how we can change the things that is already there. Let's just change the name. Or we can do it, we say M ****. The key value that you want to change is the name. So we say Midik a square bracket, a string of the key that is, in this case, name, we can say it is equal to a string max. We can do it for the integer float and list as well. We can do it the same, right? Now with that, we are changing the name inside our dictionary from David to Max. No, we want to show it. So let's just use a print in here and show it. In here, if you run, now you can see the name is changed to Max. Now with that, let's just see how we can delete one of these key value pairs. For doing that, there is two way to do that. We can say Dil or delete. Just say Dill. After that my dictionary, you should get the item key value pair that you want to delete. For example, let's just delete the weight, right? So put the weight there. So with this line of code, we delete that key value pair. Weight that is 90 completely from our dictionary. With that, let's show the dictionary. After that. Let's see what will happen. If you run, you can see, no name max height is 1.86, and no, we don't have any weight. You can see with this, we did delete it. No. There is other ways. Right now, we have name and height. Let's just see how we can delete the height, but in another way. We can say my dig dot with a method, pop, right? With this pop, we can tell it which one to delete. And here, we should give it the key, for example, the height we want to delete. We can just copy it from here to make sure nothing is wrong. And because it is a key value pair, in this case, we need to pass a value as well that for deleting it, we should pass none to it. With that, let's just print it to see if it's happening or not. In here, run again, you can see with the pop, we delete the height from a dictionary, and we did show it. You can see right now there is just the name there, right? So we learned two methods of deleting a key value pair. The difference between these two, when you delete this way, you don't get the deleted value, but with this pop, you get something in return. You can save it inside the variable, for example, A, and you can show it print A, right? So put A in there. At the end, it should print A, and you can see the value is 1.86. Why? Because we did pop the height. So that's why it returned the height to us. So we can get the value before deleting it. So that's it. You learn how you can edit a dictionary, add to it, and delete from it, and pop from. 34. 33 Tuple: No next thing that I want to talk about is topple variable. So let's just create a file for it. In here, I want to create a file. I want to call it topple dot PY. And this topple, we don't use it that much, but you should know about them because sometimes it's really important. So in here, we call it my topple, create the topple. And for creating topple, it's exactly like a list. But with the difference that you use parentheses for initiating it, right? For example, inside it, I want to say ten, a float value, 5.6 and after that, a text like David, right? And that's it. That's your topple. No, I can't tell you what topple can do, but the most important thing about the topple is what it can't do. For example, you can't change anything inside this topple. You can't add to it. You can just get values from it. So, for example, if I want to get a value, for example, this ten that is in index zero, right, we say my topple and like a list, we can get things off of it, right? Control to save. And in here, let's just run it head inter, and now you can see it will give us ten. Again, we can do it like this, give me the value that is in index zero, one, two, put two in there, know if it's safe and in here run, it will give us David that is in index two. Next, let's just see some other stuff. For example, using Colin inside it like this. Let's see what will happen. If we run, you can see it will give us everything. Next, we can do most things that we can do with the list. But the difference is that you can't add to it and you can't change anything inside it. And when do we want to use whenever we are working in a team, and we create a topple, for example, from the information that we get from the Internet, and we put it in a topple so nobody in our team can change that after that accidentally, right? So that's why use topple mostly data integrity, right? So for example, if I say my topple, let's just say we want to change the index zero to, for example, 12, right? Like this, if I save and run it will give us an error because you can't change the topple and it says it in here, topple object does not support item assignment. That's it. That's everything about topple. There are some method for topple for example, Mtopo we can say dot and you can see there is two method in here. One is count that will count one of the inputs that is in here to see how many of it is there, right? So for example, if we put ten in there, it will check how many ten we have in here. So, for example, if I add another ten in here and another ten, so now we have 310, right? Now, with that, if I put this inside a variable, we can show it. Let's just use a print. And in here, let's just use FString and over topple, there is open and closed curly braces, put a there. This is the number of times that this number ten was repeated in this topple, right? Of number ten, right? So now, if we save and run, what will happen, it says, in our topple, there is three of number ten. There is three of number ten. If we change that to four, for example, no, there is four of number ten, right? So again, if we check it, you can see there is four of them. We can do it with the text as well. So let's just say we have two David in there. Like this. And now, let me copy and paste this over here. We say B for this one, and we want to count the time that it repeat David. So let's just copy this, control C to copy it. Control V to paste it over here. Now, we want to show the B of David like this, right? So we say in our topple, there is B of text or a string, David, right? Like that. Let's just run and no you can see Our topple, there is two of a string, David. That's it. Let me show you another one, my topple. If we put dot, you can see we have index. So if you put something there, for example, 5.6, it will first check if there is 5.6 inside here or not. If there is, it will give us the index of that. So let's just show the index with the print, open and close branches around this. Now with that, control is to save and no, you can see it will give us one. And if you put David, let's see what will happen because we have two David in there. So let me copy this, paste it for this to get the index of David. Control is to save, run, and you can see it will give us two. White give us two and not this one because it go through our topo from left to right. First time that it see it, it will return the index of that. And after that, it won't search for it anymore. That's it. Now, you know everything about topo. 35. 34 Set: Next thing that I want to talk about is sits. Set is not a variable, but like a function that's really important in Python, that we can use it a lot. So in here, let me create a new file and I want to call it set dot PY, right? And in here, I want to create a set. I will call it my set is equal set open and close prances that's it. That is our set. And now with this, let's just add some stuff to it. We say my set dot add and with AD we can add things. For example, we can add a integer value to it, right? We can, let's just say, add a float value there, 5.6, for example, we can add a string, as well. So again, at this time, which is add David, and after that, just show it, right? We say print. And with that, we want to show my set. And with that done, control is to save. Now in here, let's just run it. And now you can see it will give us something like a dictionary because it has curly braces. You can see it over here, but this is not a dictionary because it doesn't have key value pair, right? So it's for sits. It's called sits. If you have a curly braces that doesn't have key value pair, it means it is a sit. And what is important about set is that you can't have multiple of one number or one text in a set, for example, if I copy this, let's just copy it, paste it over here, if we do this with the list, what will happen, I will add the David four time. But in the set, it won't do it. Let me run. You can see, doesn't matter how much you say ad, it won't add David more than once. You can see David 5.6 15. It won't add it, right? Now, when do we want to use it? Let's say we have a list of users and one new user want to register, right? And we don't want the new user to choose a user name that is already used. So let's see. In here, I want after this print my set. I want to do that. For example, we have a list, and I want to call it all user names, okay? And it's equal to David Max and Navid, right? So let's say, these are all users and no a new user want to register. So how we can do that, we can change this list to a set. And after that, try to add the new user. If it was added, it means they can register with that username. But if it didn't add, it means the user name is already exist. So in here, what I want to do I want to change this from a list that you can see in here to a set. So I will say all user names set. Okay? I will add set at the end of it. I can say sit, open and close parenss and pass all user names that are list. So this function, this set function that we use in here, either you can use it to create a set or convert a list to a set. Know with that D if you show print all user names, sit. What will happen if we run it, you can see, no, it is converted to a sit. Can see it is a set. But if we print the all user names that are just a list, let's see what will happen, how it show it to us, right? All username, if we run, you can see. First, it show it as a list because we did show all user name that is just a list and you can see it. It has a square bracket. You can see and after that, we are showing the set, and set is like this. No, let's just say the new username that you want to add, try to add it. We can save all user name set dot at. And this time, I want to add David again. Let's see what will happen. If we show the set again, you can see if I save and run, you can see it didn't change because it was already there. And that was it. In future, we talk about sets more. It was just some basic stuff that I wanted to show you about set. 36. 35 Inputs: No, it's time to talk about the input because right now we are just hardcoding some stuff inside our code, right? So what I want, do I want to create a file? I will call it input dot PY, right? So in here, I want to get a number in the input. So how we can do that, we can say input, right, and open and close parents, and we can tell whatever we want in here. For example, please write a number, right? And a semicolon and space after that. Now with that, if we run it, we say PY input, head inter. No, you can see it says, please write a number. We can put ten in there and the program will be finished, right? We put ten in there and nothing happened. What happened to these ten? This input, whenever we put a value there and head inter, this input function will return that value that you put in there and we can save it. So in here, let's just say number one is equal to input, right? After that, let's just show it with a print f string, right? The number that you enter is open close curly braces and show the num one. That's it. No licious testate. No, you can see if I put 50 in there, it says the number that you enter is 50, right? Now, let me give you another example. So, for example, get this copy it, paste it in here, and change this to num two, right? And after that, I want to add these two numbers together. So I will say sum of number numbers is equal num one plus num two, right? And after that, I want to show the sum of numbers. And in here, I want to say some of numbers that you enter is sum of numbers, right? Just with that, let's just run. First, it will tell us to please write a number. We put like five. Okay? Again, it will tell us to write another number. So let's just put two. So what will happen five plus 27, so it should show us seven. Sum of numbers that you entered is 52, what is happening. You see, when you get something from input, it will give you that number as a string. So if you want add it, multiply it, or do whatever you want, you need to first convert it to a integer or float. And how you can do that, you can do it with functions like Int, or do it with functions like float, right. So whatever you put inside these practices, it will convert it to that type. For example, if you put num one into integer, it will give us an integer value. It will convert the string to integer value. And if you put it inside this float open and close pranxs, it will convert it to a float. Now, let's see how we can use it. For example, for these two input, what I want to do, I want to convert the string that it will return to a float, just like this, put a float before it with open and close pranxs and we need to do it for this one, as well. Float. Like this, open and close pranxs and know with that, if you run, you can see first number, I will put five, next number two, and no you can see sum of numbers that you entered is seven. Next, we can do more. For example, let's say after doing all of this, again, we want another input to put their name. So in here, I will say, write your name, right? And what this will give us, it will give us a text, and we can save it inside a variable that we can call it name, right, because it's easier to do that. Now, let's show that with a print F string. So F double quotation. And in here I want to say your name is open ankles, curly braces and put name there. That's it. No, let's just run. First, it will tell us to write a number five head inter. After that, again, it will tell us, please write a number. Let's just put seven in there, head inter, and it will tell us the sum of numbers that you entered is 12 and know the name. Let's just put David there. If I head Enter, you can see your name is David. Of course, you shouldn't forget to put a semicolum at the end and with a space. So it looks more beautiful. And here, again, if you run it, eight, enter, seven, enter. The sum of numbers that you entered is 15. No, write your name. Let's just say Max this time and hit Inter. No, you can see your name is Max. No, I want to give you a challenge. We have a BMI calculation, right? So what I want you to do to get the height and weight and the name of the client and after that, calculate the BMI and show it in output. You try to do that. We will do it in next video. 37. 36 Bmi with inputs: Now we want to calculate the BMI based on the inputs. Let's see how we can do that. For doing that, I want to find the BMI. We have so much project in here, and I want to copy this part, Control C to copy it. And now in here, I want to call this one BMI dot PY, because we are making it better, right Control V to paste it in here. You see, in here, we hardcode some numbers in there, but this time, we want to get it from input. No, how we can do that, first of all, we know that it can be a float. In here, I will say a float. After that, inside the parenss we get our input. It needs a parenss as well. Now inside that, we need to tell it what they should enter. We say, please enter a number and KG garam right. After that, less add a colon and space, right? Now with that done. We need to copy and paste it for this one as well, because we want to get the height as well. So this time, we want to say, please enter a number in meter, right? Next, we want to get the name, but it's more beautiful to get the name at the beginning. So in here, let's just create a variable, call it name. And in here, we want to get it from input, right? We don't need to convert it to anything because by default, it is a string, and we want a string, right? So we say input and in there, we say, please write your name, Colin and space at the end. Know with that the BMI will be calculated. Now we can use a print F string, F, double quotation, and in here, show the result. But just say, dear, open and close prances, and I want to put the name there. Your BMI is open and close curly braces in here, show the BMI. That's it. No, let's just test that, PY, BMI, two, head tab, head inter. No, it will tell us to please write your name. I will say Max, for example, head Enter. After that, please enter a number in kilogram. I will put 19 there. After that, it says, Please enter a number in meter. So we can say 1.86 and know if I had enter, dear Max, your BMI is 26. Cool, right? Of course, it's better to change these text. Please enter your weight in kilogram, right? This will be much better. And in here, we can say, please enter your height. In meter. Control is to save. No, it will be better, right. So please write your name this time. Let's just say Navit. After that, please enter your weight in logram. So let's just say 90. After that, please enter your height in meter, 1.80, right, and head Enter, and now you can see, dear Navit your BMI is 27.7, right? Cool. No O BMI application is much more professional. 38. 37 Bool: No, I want to talk about another variable type that is called Boolean. And the Boolean variable is really important in any languages. So for doing that, I want to go here and create a file, I want to call it boll dot PY. So a Boolean variable can have just two value, either true or false, right? So, for example, let's just say Am I taller or not? And I want to say it is true. You can see the true that I'm writing in there is with big right? So when you want to put true or false inside a variable, you need to be careful about this. Don't write it in lower case. It should be in upper case, the first letter. And for false, as well, it should be exactly like this, right? But that's it. This is just a variable that can save true or false, but how we can use it, right? When I'm creating a woodan variable, a default, I will put it on none. None is just a placeholder, so we can later change it. So by default, it is none, and it should be like that. Now, with that, I want to create another variable, and I want to say average person height, right? And I want to put, like, 170 right in centimeter. No, we want to check if we are taller or not. For doing that, I want to get it from input. So I will get the height and put it inside the variable height is equal because it can be float. I will say float, open and close prantes and after that, I will say input. And in there, I will say, please, write your height, right? Just like that. And after that, we want to check if the height of the person that are using our program is bigger than average or not. And how we can do that, we can say, Ami taller is equal to height that was entered bigger than average person height. That's it. And after that, I want to show it. Print, just show AI taller, right? Just like that. No, let's just run it. PY, boll head inter. No, it says, please write your height. If I put 160 head inter, you can see it says false. And let's just run it again. If I put 190, it says, true. You are taller, right? Now, let's just run it again. If I put 170, it says, false. You are not taller, right? So what is happening in here? These are my toler. We want to use it as a bull. And whenever we check something like a number is bigger than a number or a number is equal to a number or a number is less than a number, it will give us true or false, right? So we can save it inside a variable and show it. But right now, it doesn't look good. So let's just use AF string, right? I want to say result of if you are taller than average is calibraces and show AI taller, right? Control is to save. No, let's just run. If I put 160, it says the result of if you are taller than average is false. And again, if you run it and put 190, what will happen. The result of if you are taller than average is true. You can see no, we can do the less. We can do the equal, equal is like this. If these two is equal together, it will return true. But if it is not equal together, it will return false. And like that, if I put a smaller, if the height is less than average height, it will give us true. But if the height was bigger than average height, it will give false. That's how Booleans works, and we will work with them a lot more. This was an example, so you will understand the basics of it. And here, let me change this to bigger, so code works fine. And that's it. Now, you know the basics of Boolean. 39. 38 Comparison: Last video, we did talk about comparison if it is bigger, smaller or equal. But in this video, we want to talk about it more because it's really important. So for doing that, I will create another one, another file, and I will call it comparison dot PY. And in here, let's just give you some examples. So for example, I will say print to show the result. If one equal to one, what will happen if we run this, let's just say Pi Pi, comparison, a tab, and now you can see it will give us two. White give us two because one is equal to one. So it should give us two. But if we put two in here, one is not equal to two. So that's why it should give us false. Now, let's just save and in here, run again, and you can see it is giving us falsen. It's not just comparison. We can check if it is bigger or not. So if one is bigger than two, right now, it's not, so it should give us false. If you run, you can see it will give us false. But if you put t in here because three is bigger than two, that's why it will give us true. Make sure you save, and let's just run it again like this and no you can see this is true. We have a smaller as well. Like this, three is not smaller than two, so it should give us false. Let's just run and you can see giving us false. But if you put five in here, because three is less than five, so it should give us true, and you can see, that's cool, right? No, we have more. So, for example, in here, we have not equal. So three is not equal to five. That's correct. So it should give us true. Make sure you save and run. And now you can see it did give us true. Again, if we put five in here, five is equal to five, so five is not equal to five should give false. So no, make sure you save and run, and it is giving us false. Next, what we have is bigger or equal than five, right? Let's just say three in here. Three is not bigger or equal than five, so it should give us false. Make sure you save and run and no you can see, This giving us false. If you put five in here, because five is equal to five. So these five greater or equal than five, it should give us two, right? So let's just run and you can see it did give us two. Now, next thing, if we put six in here, six again, is bigger or equal than five. So that's why if we run, again, it should give us. We have less or equal than five in here as well. So let's just test that six is not less or equal to five. So if we run, it should give us false. If we put five in here, what will happen five is equal to five. So this statement that is saying five is less than or equal than five, it should give us true as well. So you can see give us true. Now, if you put four in there, what will happen if we run because four is less than five, so again, it should give us two as well. And that's it. You know about all the comparisons in Python. 40. 39 Chained comparison: Next, we want to talk about change comparison. We want to check two things that if they are true or not, right? So for doing that, again, I want to use this file. For example, we want to say one is equal to one, this is true, and we want to check two este together. Two is equal to two or not, right? So what will happen? This we'll check. If both of these are true, it will return to. And because both of these are true right now, so that's why if we run it will give us true. But if one of them was not true, for example, put two in here, it will return false because one of these is not true. And now, if we save and run it again, you can see it will give us false. How you can translate this is like this. If this is true, and this is true as well, it will give us true. But if any of these on right side and left side and was not true, it will give us false, like we have it. For numbers, we have it for a string as well. So for example, in here, we say David and in here, we say David, as well. So if this is equal to this one and this is equal to this one, it will give us true. That in this case, it should give us true, right? Run, and you can see it is true. But if you change this to Mx, what will happen if we run because this one is not true and this one is true, this end will return false. So just run and you can see it is giving us false. Now I want to talk about another one or so or what it will do, it will check both of the statement and the left side and the right side of it. If one of them was true, it will return true. But if both of them was false, it will return false. So in this case, because two is equal to two, that's why doesn't matter if this is true or not, it will return true. So if we save and in here run, it will give us true. So if we change this to one, because both of the statement at the right side and left side of the is false. In that case, it will give us false. You can see. But if both of these cases was true like this, again, it will give us true because or needs just one statement at the left side and right side to be true. If one of them was true, it will return true. But if both of them was true, all the better, right? I will return true, as well. Now, if you save and go here, run, you can see it will give us true as well. Now, you know how you can chain comparisons together. 41. 41 Improve BMI program with statment: No, we want to improve our BMI application. Let's see how we can do that. In here, you can see if I put the height 180 and the weight like 90, what will happen if we compute, it will give us 27. And based of these categories, we can say if we are underweight, normal weight or overweight or obesity, right? So we can check all of these, right? Let's see how we can do that. In here, I want to find our BMI that we have in here. I want to copy it and create a new file, and I want to call it BMI dot PY. You can see we are making it better, right? Control to paste it over here. No, we are calculating the BMI, but we don't want to show it like this. We want to tell the user if they are fat or not, right? So we want to check the BMI. So let me put this aside so you can see both first, if the BMI was less than this value, let me copy this value. It means we are underweight, and you can see if it is equal or less than this value. It means they are underweight. So we can say in here, if BMI was less or equal than this value that we copied after that column, we can say print. I want to use FS string because we know FS string how it works. Your BMI is clibras BMI, right, and you are underweight. That's it. Control S to save. Next category is normal weight. If the BMI was between this value and this value, it means they have normal weight. They don't need to have any sort of diet, right? So in here, I want to check it with LF, right? And in here, again, we want to check the BMI. If it is bigger than this value, 18.5. And with the end, we check if BMI was between 80.5 and 24.9. So we can say I BMI was bigger than this and BMI was smaller than 24 dot nine, right after that, we need a column. And in here, we want to print that you have a normal weight. So paste it over here. I showed the BMI, and in here, we say normal Wait. Cool, right? Next thing that you want to check, we want to check if the BMI was 25-29 0.9. If it was this, it means you have a little bit of overhight, right? So again, we can use another F. You can do this kind of LIF as many as you want. Again, we check BMI is greater or equal than 24.9 and BMI was less than 29.9 after that a colon, right? So in here, we want to print that you have overweight, right? We can change this to overweight. And if none of these cases was true, we can use as after that a colon, and we can say print for example, let's say danger, B city, right? That's it. No, with that, let's just test it. If we run or code, the name max, for example, the weight, let's just say 70 and the height, let's just say 1.9. That's it. It is a meter. Head inter. No, it says, You BMI is 19 and you are normal weight. That's cool. Let's just test that. In here, if I put 190 and in here, put 70 compute, you can see, we did calculate it correctly. Now, let's just test it with some more variables. For example, Max. Again, in here, the weight, let's just put 120 this time, right? And the height 1.7, right? And you can see it says danger obesity, right? Again, let's just run it one more time. Max. Let's just say 92 this time, and the height 1.86 head inter and you can see your BMI is 26 and you are overweight. Again, if I check this, it should be correct. The height 186, the weight 92 compute, and you can see 26.6 correctly and 26.6, you can see it is in this category of overweight. So no BMI program is working flawlessly. Congratulations. 42. 42 For loop basics: Now it's time to talk about for loop. In Python, when we have a list and we want to check all the item inside it and, for example, show it, we use for loop. So let me create a new file in here. I want to call it for loop dot PY. And in here, I want to first create a list. So I will say my list. Is equal to some stuff, right? For example, a text, David, after that, a integer number, after that a float number, after that really big value. After that, another text, for example, Max. After that, let's just say another text as well, like Apple, right, like that. So you know that how we can get one of these items and show it in output, right? So we say my list and after that, with a square bracket in here, we can say, for example, give me the item in index zero, one, two, three, right? Give me that and with that, we can save it inside a variable. For example, A is equal to my list item three of our list. And after that, we can show our variable A, right? With that, let's just run it. We say PI four head tab, and it will put the rester head inter, and now you can see it is giving us that exact item in index, we save it inside a variable, and after that, we show it. No, I want to show you how we can check all of them and get each one of them one by one and show it in output. For doing that, we use four loop. For four loop, we say four, and in here, like we define a variable in here, I want to define a variable B, for example. After that, we say NO list, my list, right? After that, colon and no, what will happen with this line of code, it will go through our list one by one. And each time from the first index, it will get that item. It will save it inside the B variable that we create in here, and no, we can show that variable, the B variable in here. So I can say print B, right? And again, like I that we talk about, this indentation is really important. So until you have indentation in here, it means it will run that code for that variable, right? So, no, let me run it and after that, I will explain it more. If I run, you can see first, it will print A that is this, and after that, it will start from index zero. It will get that item. It will save it inside B, and after that in here, it will show it like you see it in here. Next, this four loop goes to the next index. Next index has ten in it, right? So it will save that ten inside the B as well, and again, run this code with that variable. And you can see show it in here. Again, this four loop will go to the next index that is 5.6. It will save it inside the B variable and let you do things with it. For example, printed, right? So you can see it did write 5.6, and it will do it to the end, that is over Apple, right? This is the four loop. And for you to understand it better, I want to delete this, and I want to change this variable to, for example, item or whatever. And I want to show that item. No what will happen. This four loop will get each one of these items inside this list from the beginning to the end one by one, it will save it each time inside this variable, this custom variable that we create in here and let us do things with it. Beneath the four loop if it has indentation. Now with that done, make sure you save and run, and now you can see it is exactly like before I start from Index zero. Get the item, save it inside the variable that we create in here, and know we can do things with that variable, right? That's it. That's our for loop. Let me give you more example in future videos. 43. 43 For loop challenge: No, let me give you another example. For example, in here, let me create another list. I want to call it my num list, right? I will call it my num list. You can call it whatever you want. And put some random value there, right? Like this, like this and like this, some really random value. And this one, right? Doesn't matter what you put in there, we want to just have some fun with it, right? Let me some more, and that I think is good. No, you see, we have a four loop for showing all the items inside our list, my list in here that has everything inside. But now we have a list that has just numbers. I want to give you a challenge to just print the odd numbers in this list. So you need to use a four loop to check which one of them is odd and which one of them is even and show just the odd ones with if statement. So before doing that, I want to give you some tips so you know how to do it. As you know, whatever line of code that you put with four indentation after four loop, all of those codes will happen to that item, right? But if you want to go to a new line and do something new, apart from this four loop, you can go down and delete the four indentation space in here, right? So for example, in here, I can create another four loop. I can say for num in my num list, with a colon at the end of it, no, we can't print it, right? Print everything. Print the number inside it, right? Control to save. No, first, this four loop will happen, and when it's finished, it will go to next line and after that, it will go to this four loop. And what this four loop do each time it will get one of these items, and it will put it inside this num variable, and it will run all the code benefit if it has indentation, right until it reached a line that doesn't have a space indentation, right? Now with that control is to save and if you run, you can see first four loop will happen to the apple, as you can see here. And after that, it will print everything, all the numbers, right? No, if I want to do something after all of this and I want it to be apart from the four loop, I can just delete the for space indentation and for example, use a print. And in here, I can say, print, finish. Execution, right? That's it. Control is to save and no if you run, you can see the finished execution will happen at the end of these two for loop, right? No next thing for you to do the challenge of this video is to use mod or person. For example, if I use a print to show 25 mod or person two, what this will give us. If it give us one, it means it is odd number, and if it gives us zero, it means it is even number. So in here, if I save and run, you can see it did give us one, so it is a odd number. But if I change this to 26, no, it will be even number, and if I run, you can see it is giving us zero. So with knowing all of these, you need to solve the challenge. Just print the odd values inside this list. You try to do that. We will do it in next video. 44. 44 Challenge soulotion: No for printing the odd numbers. First of all, what I want to do I want to use printing here. To create a line between these 24 loop. So you can see it better. In here, I will say showing all odd numbers, right. So with that down, if we use Control S and run, you can see, first, it will run the first four loop, and after that, it will go for the next four loop, and before that, it will say showing all odd numbers, right? Now in here we don't want to print everything. We want to check if with the IS statement, if the number mod or person two was equal to one. Colon after that. We go to next line. Disenentation is really important. If num mod two or person two was one, it means it is odd number. So with that, we can print the number. But if num person two was not equal to one, nothing will happen. It won't print, right? This print num won't happen anymore. So control is to save. If I run nu, you can see showing all odd numbers, and no it's just showing the odd numbers in our list. Now I want to give you another challenge. We are showing the odd numbers. I want you to create another four loop. Don't use this one, create another four loop, and with that, show all the even number. Like we did it in here, we say show in all odd numbers and we show the odd numbers. And after that, you should say show in all even number and show those even numbers. You try to do that, and we will do it in next 45. 45 Get all even numbers: No, for showing all the even number. The only thing that you want to do, we can just copy all of this, Control C, go down, delete all of this indentation because we need a new line. We need a new four loop, Control V to paste the code in here. This time, we want to show the even number. So change this to even number. And after that, change this one to zero. So what will happen? This four loop will get each one of these items one by one and put each one of them inside this num variable, and it will run all the codes beneath it if it has four space indentation, right? So for each one of these, this if will happen. And if that number person two was zero, it means it is even number, and we can show it. But if it's not equal to zero, it means it is not even number and we don't do anything about it, right? Control is to save and know if I run. First, it says, showing all odd numbers. I will show all the odd numbers. And after that, it says, showing all even numbers and no you can see, it's showing all the even numbers for us. Beautiful, right? So we can use I a statement inside for 46. 47 Total price calculation: Now again, another challenge. These challenges will help you to remember everything. So in this challenge, create a list of numbers five number, for example, don't make it too long. And with a four loop, get all of them and add them together, right? So what do you want to do? We want to get the sum of them, right? So you try to do that. We will do it in a second. No for creating that list. I want to go here. I want to say item, but prices, for example, right, it's equal to a list. So list of the item that you bought the prices of them, right? For example, one of them is $5. One of them is $7, one of them is $10, and one of them is $20, right? And right now, we want to get the sum of them to see how much we did spend, right? So 20 by ten is 30 by 737, and by five, it will be 42, right? So we don't want to do it like this with a calculator or or mind. We want to write a code. To calculate that. So for doing that, again, we can use a four loop. And before doing that, I want to use another print. And in here, I want to say total price, right. And after that, use a four loop for, let's say, item in item but prices, right? And a column after that, know we are getting each one of these values one by one. And it will save it in item, and now we can add them together. But when we are adding them together, we need to save it somewhere. Where can we save it? We can go up here and we can create a variable for it. So we can say, total price is equal, by default, none, or you can just put zero in there, right? That's it. Now with this total price that by default, it is zero in here, head tab. So we make sure we have the right indentation. So all the codes will happen when these four loop happen, right? In here, we want to say total price is equal the total price plus the item item that we know will be the prices that we put over here, right? It will give it to us one by one in here and we add it to the total price, and we save it inside the total price, right? So now with that, we can show that. You can say print and show the total price. That's it. Control S, add a space in here, so it will be more readable and know if we run you can see it says, total price is 42, exactly. Let's just add one more to it. For example, $8, right? Control to save. Now in here, if you run, you can see 50. So everything is working fine with this total price. You can do other things as well. For example, if I put this total price print, Control X to cut, and put it beneath the four loop with the right indentation for a space indentation and show it what will happen each time that this four loop go through any item, each item one by one and save it inside the item and add it to the total price, it will show it right away each time. So what will happen, we have one, two, three, four, five of them, right? So five times the print total price will happen, and first time it should five plus zero. By default, the total price is zero. So five plus zero, it should show five. After that five plus seven, it should show us 12. After that 12 plus ten, it should show us 22. And each step on the four loop, it will show it to us. Control is to save, and know in here, let's just run it. And now you can see the total price first item is five plus zero. I will give us five, five plus seven, it will give us 12. And after that, you can see it reached 50. But I don't want to do it like this. I just wanted to show you that you can have multiple line of code beneath the four loop. After that, we can use a print a string, right, to show it in a better way. So we can say total price is with curly brackets or curly braces in here, we can show the total price. That's it. Control is to save. Now, in here, if you run at the end, it says, total price is 50. This was another example of using four loop. 47. 48 For loop on string and tupple: Like we did the four loop for the list that we mostly do it for the list. We can do it for the other things as well. Let me show you something. In here, let me create a new file. I want to call it four loop dot PY. That's it. Now in here, I want to use four loop on a string. So we need a string. I will call it my STR is equal to let's see, hello word, right? With that done, we can use a four loop like this four, whatever you want, you can call this variable. I want to call it car or character or whatever you want to call it in my CR, after that, a column, right. After that, if you put whatever code beneath the four loop, if it has four space indentation, it will happen for each one of these characters. For H, it will happen, for E, it will happen, for L, it will happen. So what will happen, these four will get each one of these characters, and it will put it inside this char variable, and we can do whatever we want with that character. So for example, let's just say print, right, and show the car or character. That set control is to save. In here, I want to run for loop two, so head tab, so it will put for loop two in there, head enter. Now, you can see it says HELLO space. We have a space. The space is another character, right, WORLD, right? So with the four loop, we can loop through a string with its characters, right? So now with that done on to go to next line. Here, go to beginning, so I want to create a topple. So in here, I will call it my topple is equal to open and close parents. And in there, let's just put some values there. Like 2,055.6, a text, for example, max, and after that, some value, one, two, three, right. Whatever you want, you can put in there. Now with four loop, we can loop through all of these like we did it for list and we did it for text. So in here, I can say four we need to declare a variable in here, whatever name that you use, it will be okay. I will call a for example, in this case, in after that my topple, right, and after that, a colon, don't forget the colon there. And with that, let's just show it, right? With the print, we want to show the right? So what these four loop it will get each one of these items one by one, and it will put each one of them inside this variable, and we can decide what we want to do with that item that we get from the topple, right? Control is to save. No. Let's just run it again. You can see it will start from 25, 5.6 max one, two, three, and it will show everything for us. That's it. So you know we can use four loop with strings and topple 48. 49 Tupple unpacking: No, I want to show you topple unpacking. This is a neat trick that we use a lot. So our code will be efficient and much easier to work with and readable, as well. So what I want to do in here, I want to create another one, another file, and I want to call it topple unpacking, right? Dot PY. While I'm not calling it for loop because we want to use for loop in here. But while I'm not using for loop name for it because it's really important. And in future, I want you to be able to find this really easy because it's really important. Let's say, we have a list, and I want to call it my list is equal to a list that has some topple inside it, right? For example, one and two. Next topple, again, let's just say three, four, and next topple. Let's just say five and six, right? Now with that done, let's just see how we can use for loop on it. So we say four item, for example, in my list, right? Column after that and in here, let's just show it. Show the items. We show printing item. Control S to save. In here, I want to say PY, topple packing and head inter. No, you can see it is giving us tree topple, right? But W saying that it's really cool. Right now we are just getting some topple, right? Nothing cool about it. But we can get the items inside this topple with a four loop directly. Let me show it to you. Can you see to copy this and let's just paste it over here like this. Know what I want to do. I want to say, with this four loop, get the least items, and because I know that or least has topples inside it, unpack it and save it inside these two variables, for example, A and B. That's it. And we can put it inside a parentheses so it looks more readable, just like this. I love to use it in a parentheses. This way is much better. So know it that this follow, what it will do first, it will check all the item, and it will give us all item one by one. But how it's saving it, it will save the one, for example, in A and two inside B. When you doing that, we can just show the A, for example, for no, of course, right? Next in next loop, what it will do it will give us this topple and three will be saved inside A this time, and four will be saved inside B. And because we are showing just A, it will show us three and so on. Let's just test that I run it in here. No, you can see it is giving us one, three, five, one, three, five, all of the A's, right? But what I'm saying it's cool because let me show you something. In here, we can directly say A plus B. So what it will do, it will give us the sum of the numbers inside the topple, right? So with that control S to save and run. No, you can see one plus two. I will give us three and three plus four, it will give us seven and five plus six, it will give us 11. You can see how much we can do with just one line of code. We don't need to go through each topple. Just with that, we are unpacking topple. But you may say, This is not that cool, right? But in next video, let me give you another example that makes more sense. I will see you in next. 49. 50 Tupple unpacking tricks: Now, let's see what is brilliant about topple unpacking. For doing that, I want to create a new file. I want to call it topple unpacking to dot PY, right? And in here, I want to create a list of topples that has key value pair. I know it's confusing, but you will understand why we are doing this. So in here, I will call it temper chars, right? And in there, we want to create a list of topples, right? And I can put whatever I want inside this topple, but what I want to do I want to create some key value pair, like dictionary. But this is not a dictionary. It's just list of topples, right? So in here, I can say London and after that, the next input, I want to say, it is 35 degree, for example, right? After that, let's just add another one in here. We want to say Texas, right? And it's temperature. Let's just say 58 degree, right? After that, just add another topple. This one first, I want to name it NY for New York, right? And it's temperature. Let's just say 25. And with this know what we have, we have a list of topples of city temperatures, right? So with that, we can use a four loop with topple unpacking, for example, in here, I want to tell the four loop to grab each topple and put it inside these two variables. For example, let's say this is city name. So first item of topple, put it in city name. And after that, the next item inside the topples, put it in temp or temperature, right? And after that, we want to say in temperatures. After that, a column, and know with that. We have access to all the cities and the temperature, and how these four loop doing it, first, it will get this first topple and it will put London inside the city name variable, and it will put 37 inside hemp variable, and now we can do whatever we want with it. So we can say print. We can use a F string, right, like this. And in here, I want to say temperature of open and close curly braces. In here, I want to show the city name. And after that, I want to say is, again, another curly braces and show the temp. And after that, I can save degree, for example, right? And with that done, let's just save and in here. I want to run topple packing to head inter. No, you can see the temperature of London is 37 degree. The temperature of Texas is 58 degree, and you can see it, it's correct. Temperature of New York is 25 degree, and you can see it over here. So, now with this topple packing, we are creating a key value pair that with it, we can loop through every city and show its temperature with its name. So that is what's brilliant about topo unpacking, but we are not finished yet. Let me explain some more in next video. 50. 51 Use for loop on dictionary: Topple packing is important in other places as well. For example, using it with dictionaries because actually from Internet, you get a dictionary first, and with that, there is a method on that dictionary that will give you a list of topples. That's why the topple packing is that important. So for doing that, in here, I want to create a new file and I want to call it for loop with dictionary, right, dot PY. So in here, let's just create a dictionary, and I want to call it my dict. Is equal, too? If you remember, we should use curly braces for a dictionary, and it needs to be a key value pair. So, for example, in here, I want to say, like before, London, the value of London, let's just say 28 like this. And after that, let's just say Texas, right? And the value of Texas key is 54, for example, this time, and after that, let's just add another one N Y or New York. And the value of it, I want to say 23, right? And with that, we have a dictionary, and let's just print it to see what will happen if we print it, right? We say my dict in here, control is to save and in here for run it, we say PY, four and four bit dictionary head Enter. Now, you can see it is giving us a dictionary on output, right? But let me show you something. Let's just use a four on it, four loop on it. So in here, we say four, for example, let's just say item. In my dictionary, right. And with that, let's just show the item that four loop is getting from the dictionary each time and put it in item. So in here, if I show the item, just like that, let's see what will happen. Control is to save run. And now you can see it is giving us the keys. London takes us and N Y. So when we are using four loop on a dictionary, it will give us just the key, right? As you can see in here, London Tis us and New York. So it is giving us a key, but how we can get the values. So in here, if we put dot after that, you can see we have some methods. So for example, if we say keys and add a open and close prances, let's see what it is giving us. In here, run, and you can see again, it's giving us keys again, right? But we are not interested in the keys. So let's see how we can get the values. So in here, we say values and open and close prenss. Now, let's see what will happen. If we run, no, you can see it is giving us just the values. But in one for loop, we want to get both of these key and the value with it. So before that, we show the temperature of city is, for example, 25 degree, right? You want to do the same in here. How we can do it, there is a method in there that is called items, right? Now with these items, method, let us see what it is giving us each time in item, right? So in here, let me run. Now you can see it is giving it to us as topples. You can see open and close parentheses. So with these items method, we are converting our key value pair to a topple. And the cool thing about it is that we can unpack this because we know that this is a topple. So in here, we can save it inside the variable. Open and close, prances, you don't need it, but it will be more beautiful to do it this way. First, input, I want to put a city name. So first variable will be city name. And the next variable, I want to say Temp, right? So what this will do now because of the items method, it will convert this to a topple and it will put the London inside the city name, and it will put the temperature inside the temp. Now we can show it. For example, like before, use F string, right? So in here, you want to say temperature of city. For example, curly braces, city name is again, curly braces, and in here, put temp in there, right? And after that, let's just say degree like before. Rule is to save no you run. And now you can see the temperature of city London is 28 degree and you can see it, it's correct. No temperature of City Texas is 54 degree, and you can see it is correct. So no with that, if we get a dictionary from Internet, we can convert it to a list of topples with these items method. And with that, we are getting the key value pair in just one for loop, right, just like that. So that is what's brilliant about topple unpacking. 51. 52 While loop: No, it's time to talk about while loop. So for doing that, I want to create a new file and I want to call it whileloop dot PY, right? And here, for creating a Vile loop, you say Wile, I will explain everything. Don't worry. You say just while and after that, a condition that can be either true or false, right? So in here, let's just say true. So if we do that after that column, you can go to next line. And while it is true that it will be always true, we can run some code. So for example, we can use input. For example, let's just say write your name. Right. And after that, this input will give us a string that we can save it in name variable, right, like that. And after that, we want to show it, right? So print and show the name. That's it. Control is to save. Now in here, we want to say Pi, while put WH there, head tab, and it will put the rest for you, head inter. Now, you can see. It says, write your name. If I say Max, it will show the max and after that because this while is true, that's why it will go back and it will run it again. So in here, if I say David again at Inter, it says, David, and after that, it will tell you write your name. So while this is true, all of this code will happen over and over and over again until we use Control C to break the execution of code, right? That's it. Control C. So this while true will always happen because this is true. So while it is true, get the name and show the name, right? But if you put false in here, let's see what will happen. If you put false in here, run, you can see nothing will happen because this is false and none of this code will happen, and you can see it is grade out a little bit, right? So we as code knows that because it's always falls, this won't happen at all. But what we can do, we can create some other conditions. For example, I want to say, for example, count is equal to zero, right? That's it. And we want to say, while count is less than ten, for example, right? Run this code. But what will happen, the count is zero and zero is less than ten, so this will be true. And this will always happen over and over and over again. So each time that this code is happening, we need to increase the count, so it will happen just ten times. So in here, we can say count is equal count plus one. That's it. Now, the count will be increased. And with that done, I want to use a print to show the count, right? And I want to use FS string, and I want to say count is curry brackets. And in here, show the count, right? That's it. No, let's just save and run and no, you can see if I put max in there, you can see count, no is one. At default count was zero, no, the count is one. And again, let's just put some value. Count no is two, put some more value, count three, count four, six, seven, eight, nine, and ten. And after ten, you can see it did exit out of or code, right? I don't want to get an input always, what I want to do. I want to delete this, so it will be easier to test it. So what will happen? Count start from zero, and it will reach ten, right? So let's see. In here, let's just run, and you can see count is a start 1-10. If you want it to start from zero, because it is starting from zero, you can just cut this print and paste above this count plus one in here, right? So now with that, it will start from zero, and it will reach nine. And when it reached nine, it will add one more to this count, and the count will be ten. And again, this i loop check, know that the count is ten, ten is not less than 1010, is equal to ten. So that's why this won't happen anymore. So let's just run one more time, and you can see the count is 02, nine, ten times it did happen because the count is starting from zero. That's it. Now you know how you can work with L 52. 53 While loop challenge: No, it's time to give you a challenge. You know how to work with a VI loop. I want you to create a Vil loop that say hello 20 time, for example. You try to do that. We'll do it in a second. So for doing that, let me create a new file. I want to call it Wil loop two, that PY. Now, for a Vil loop, we need a counter, right, a variable, so we can increase it and check it as a condition of our illoop, right? So for example, in here, I can say, counter is equal to zero, and no, I want to use a Vil loop. So while a empty space, and after that, I want to check the counter. If it is less than 20, we want to print hello. So I should say print Hello. Knowing that we need to increase the counter each time that the print hello happen by one. So we can say counter is equal counter plus one. Or you can do it in more efficient way, you can just say plus equal to one. That's it. This will do the exact same thing to say counter is equal counter plus one, right? So this line of code, it will increase the counter each time that it's to be run by one, and it will say that inside itself. Now, let's just say Sato. No in here for running. Just head tab, head tab again, while loop two, head inter. No, you can see it's print hello to time. I don't want to write it. Let's just put five in there to see if it's happening or not control. Es save. And here, run, can see one, two, three, four, five. So if you put, for example, 100, it will happen 100 times. So let's just run, and now you can see 100 times we print Hello. No, I want to give you another challenge. Create a V loop that will get all the even value 0-1 thousand and show it. So again, create a Vi loop that it will print all the even values 0-1 thousand. You try to do that. We'll do it in next video. 53. 54 While loop even challenge: Know for printing all the event number 0-1 thousand. Let's see how we can do that. I want to create a new file for that. I will call it Wild ooptre dot PY. And with that done, again, we need a counter. You can call this counter whatever you want, but this way, it's much cleaner and readable. I want to put it to zero, right? And now with that done, I want to use a Wil loop, and I want to check the counter until the counter is less than 1,000 after that a column, know what you want to do in here. We want to check it with the If I counter. Mood or person two was equal to zero. It means it is an even number, right? So we can print it, print. Counter. That's it. No, after doing this, we need to increase the counter, right? We don't want to do it inside this I. We want to do it after the I. So it's always happen, doesn't matter what. Every time that this y loop happen, we need to increase the counter by one. So plus equal to one, and that's it. Control is to save. Now if I run the Wy loop tree, you can see it is writing all the event number 0-1 thousand. And if you check it, you can see there is no odd number in it at all, real easy, right? 54. 55 While else: Wil has another thing that is called s. So I L and s that we talk about it, we have s for le as well. So let's just create another file, and I want to call it Wil Loop for that PY. Now in here, let's create a counter. I want to call it I and I want to equal it to zero. After that, I want to say Wile I is less than six. After that, the colon, and I want to show the I, right? Show I. After that, we need to increase I, so I plus equal to one. And with that done, what it will happen if I clear here and run this wild head inter, and you can see it is a start 0-5 because after five, it really is six and six is not less than six, so that's why it won't print the six. But when it reaches six, the else will happen, right? So let's just see how we can use se. In here we say se and after that, the colon, and in here, we can say print. And let's just say I is six, and it is not less than six at all. It is equal to it. It's not less than that. Now with that, if you run, you can see it will print 0-5. And when I reach six, this six is not less than six, it is equal to six. So these codes won't happen and the else will happen. So at the end of you, when this statement is not true and it is false, the else will happen. So if you want to look through something and at the end of it, you want to do something with all of those informations and variables, you can do it inside else. 55. 56 Continue and break in loop: There are two things about any loop doesn't matter y loop or for loop that you can do, but we don't use it that much. But in some codes, when you are in a team, you may seize those, so I want to explain them as well. So in here, let me create a new file and I want to call it break continue dot PY. So it doesn't matter what loop you are using, you can break out of that loop whenever you want, and you can ignore one of the loops. So let me give you an example. For example, in here, let's just say I is equal to zero. And we want to say, while I is less than six and a column, we want to show the I with print, right? That's it. And now, in here, I want to say if I is equal to three, what I want to happen, I want this loop to break completely and get to of the loop completely, right? But if it's not three, increase the I by one, just like. And after that, let me add a print at the end of or code, and I want to say finished Execution, right? So this print finished execution is outside of the le. It's outside of the I. It will happen always at the end of our code execution. Now with that done, let's just run it. We say Pi, break. Head inter, know what will happen. It will start from zero. Zero is less than six, and it will print zero. You can see it did print zero. And zero is not equal to three, so it won't break, but it will increase I. Noi is one. So it will go back to the loop and it will run the code. Noi is one. One is less than six, so it will print one and one is not equal to three, so it won't break the loop. And after that, it will increase it again by one until it reached three. No tree is less than six, and it will show that it will show the tree. But in here, it check. If the tree that right now it is tree is equal to it will break the loop, and it won't increase this at all. It won't run this line of code at all. So it will break the loop completely, and it will go to the next line, and it says finished execution, and you can see it in here. It will start 0-3. After that, it finished execution. That's it. That is about break. No, another thing that I want to talk about is continue. Like the break, we have continue as well. So in here, what I want to do I want to say finished break execution, know what I want to do. I want to show you how continue works. In here, I want to say, for example, J is equal to zero, like we did it in here, we did call it I in here, I did call it J, right? In here, I want to use Wil and I want to say. While J is less than six exactly like before, after this, what I wanted to happen in here, first of all, I want to increase J by one, and after that, I want to check if J is equal to three. In that case, continue. I will explain what continue do. But after this F, what I want to do, I want to show the J. So print J. And in here, I want to copy this print so you know when it's completed, right? Like here, and I want to say finished continue execution, right? Now, if I run, what is happening, it's showing one, two, four, five, six. What does happen? Let me explain. J at the beginning is zero. Zero is less than six. So this code will happen and no J is one. One is not equal to three, so this won't happen, and it will print one. You can see it over here. No, again, it will go up in the loop, and because the J right no is one, one is less than six. So that's why this code will happen. And J will be two after this. Two is not equal to three. So that's why this continue won't happen, and it will show two, right? You can see it over here. No, it will go up. No, J is two. Two is less than six. So this code will happen. With this code, J is three no, and three is equal to three, and the continue will happen. And what this continue will do, it will prevent the codes after that to happen. Make the loop to ignore the line after it inside the loop and it go at the beginning again. No J is three. Three is less than six. So this code will happen three plus one will be four, so no J is four and four is not equal to three, so it will print four. And you can see it is ignoring three because when the J is three, we say continue or ignore the codes after that in the loop. That's it. That's how break and continue works. 56. 57 In operator: No, I want to talk about in operators. It's really a neat thing in Python that you should know about. So in here, let's just create a new file. I want to call it in operator dot PY. So what this will do, for example, we have a text, my STR, right? We have a string, and let's just say it is hello word, right? And with that, we want to check if there is W inside this string or not. So how we can do that, we can say W in o my SR. So what will happen in here, this in operator will check. If there is W in the MSTR variable, it will return true. So in here, let's just use a print to see what it will return like this. Control S to say in here, let's just run the in operator run, and you can see it is giving us true because there is a W in here. But if you change this to A, let's see what will happen. If we run, you can see it will give false. We can do this with list as well. So if I say my list is equal to a list, for example, let's just say Max. After that, let's just add some integer number, some float number, and some more value like this value and more float value and some other texts, David, right? So know that we can use this in operator with a list as well. So in here, we can say print because we want to show the result. We want to say if there is ten, number ten in my list, right? So with that done, control to save. Now, if you run, you can see it says true. So there is number ten inside in here. But if you change this to 11, control to save in here, run, and you can see it is giving us false. Now, let's just do it with the text. For example, if I in here say max control is to save and run can see this is giving us true. And if I change this to Hello, for example, what this will give us because there is no hello in this list, what will happen. If you run, it will give us false because there is no hello in there. But let's just check something. If there is inside this list, there is max in here, but there is no inside this list. So what this will give us, it will give us false. Let's just run and you can see this is giving us false. So we can check if there is something in other things. That 57. 58 Librarys: No, it's time to talk about the libraries that is inside Python. Let's see how we can use them. In here, I want to create a new file. I want to call it library dot PY. And in here, first thing that you want to do, we want to import the library and tell which one of the library function we want to use. I know we can do that. For example, I want to create a random integer, and there is a library for that. For doing that, we say from after that name of the library that in this case, I want to get a function from random library, and from this library, we can import a function. For example, random integer. You can see we have random integer. That's it. Know we have access to random integer or Rad Int insight or random library that is a part of Python. Know with that do, we can use it. So, for example, let's just use a print and use this rand Int in here. It is a function. You can see it says, return random integer in range A and B, including both end points. So, for example, I want to tell it to give me an integer value 0-100. And now let's see what will happen. If we run the library file, you can see it is giving us 57. And again, if you run it, again, it's giving us another value. Again, if you run, again, it is giving us another value. Again, we can do lots of things with the functions that is inside this random library or random module. So we say from random, right, Import, after that, you can use controller space to see all the functions that is inside it. For example, if you go down, you can see shuffle in here. If you hover over it, it will tell you what it can do. It can shuffle list in place and return no. So what it will do, if we have a list, it can shuffle it around, right? So for example, if you have this list, my list is equal, let's say, one, two, three, four, five, six, seven, eight, nine, and ten, right? You can see if I print this, my list no luscious run. And now you can see, our list is really in order, right? But if we use shuffle on it, let me take this, grab it and put it up here. Because I want it to be more readable. Now, if I use this shuffle function, I can do shuffle, and inside it, I want to say shuffle my list, right? So know what will happen. It will shuffle up the list, and it will save it inside itself, right? It will return none. If you are already, you can see it is shuffle least g in place, and it return none. So just with that, if you print the last is my list, and control is to save and run it. You can see first, it is ordered, but after that, we did shuffle it. So that's how you can use the libraries or methods or modules that is inside Python. 58. 59 Librarys from internet: We did use the library or modules that is already in Python, right? Like Random module or random library. But there are a lot of libraries in Internet that we should be able to download and use them. Let's see how we can do that. For doing that, I want to create a new file and I want to call it library two dot PY, right? And in here, the module that I want to use, first, we need to install it, download it and install it. And how you can do it, you should go to terminal and say PIP, right, Install. It's called Pi Piglet. Okay? Just paste this and Python installer will go and download and install it for you. Head Inter. If you are getting a row with PIP Pi Figlet, you need to use PIP Tree, right? If you are on Mac or Linux, use this PIP tree in install. Pie fig let, right? They like this, Pip tree. If the pip itself is not working for you, just add a tree at the end of it and it should work. And now in here, you can see it is successfully installed pie figlet. Now let's see how we can use it. For using it, we can just use import, Pie figlet like this. And with that done, we can use the functions or method inside it. Let's just test some functions inside. Pie, Figlet jot. It won't show anything, but it's okay. Sometimes these kind of things happen. The function that you want to use inside it is called FigletUnderscore, format. And we can add the open and close prances and put something there. For example, hello word, right? So what this will give us, we can save it inside a variable. So let's say A is equal to this. Now, let's just print A, print. A, right? Let's see what will happen. Control S to save and in here, let's just run it. And now you can see it did write hello word in a graphical sense. You can see. So whatever we change in here, for example, if we change, my name is Max. Control S to save and run, you can see, my name is Max. Now I want to give you a challenge. Use this library or package or module. To get the text from input and show it this way, right? So you try to do that. We will do it in a second. So for doing that, what I want to do in here, I want to add an input, right, input. And in here, say what you want, right? After that, we want to save this inside the variable, so I will call it a string to show equal to this, and no I want to use this variable instead of hard coding things there. So in here, I put a string to show, right? With that control is to save. Now if you run, let's see what will happen. It says, say what you want. I will say David, for example, head tab. No, you can see it's showing David. Again, if you run and put Max in there at Inter, and now you can see it's showing Max. Congratulations. Now you know how you can download and install packages from Internet. But where these functions is coming from it's like our VS code can't auto complete that. Sometimes these kind of things happen. You can use Control C to copy it. Now go to Google and in here, paste the name, right? If we search for it, and the first result, let's just open that. And now you can see it is giving us all the information over here, how to install it. You can just copy it from here. And if you go down, you can see it will tell you how you can do other things with it. It will show you the functions that you can use in here. So you can see everything is inside this page. So whatever you want to do, just search it in Google, find a library for it, and go to its page, and you can just copy and paste some code. For example, these ones, right? And you can see, we can change the font as well. We can do lots of things with these kind of packages. And in future, we will learn about more packages. I just wanted to show you a simple library to use so you have experience as a beginner how to download and install a package about the problem that we had that autocomplete doesn't work sometime. When you install something, you can just close VS code and open it up again and now you can see it can autocomplete for us. For example, if I use Pi Figlet and a dot after that, you can see it will give us all the method inside it, for example, Figlet format. And if you hover over it, it will tell you how you can use it, right? That's it. Just close and open VS code one time and the autocomplete will work. 59. 60 Use from import on pyfiglet: No, I know you noticed something. In the last library, we say from random module or library, import a function, right? But in here, we didn't install and download a package or module from Internet, and we just say Pi figlet, right? We say import Pi Figlet. That's it. But I want to show you how you can do it exactly like here, because right now, because it is an assault, you can use it exactly like we use it for the modules and functions that is already in Python, right? So in here, in a sing like this, we say from Pi Figletimport a function. What function? Let me head control space and you can see it show us all the functions inside it. And the one that I need is FigletFmat. That's it. Now with that done, we don't need to say Pi figlet dot FigletFmat. We can say FigletFmat. That's it. That's all you need to do. So you import a function from the module or library, and you can use that function wherever you want. This way, I think it's much cleaner, but I wanted to show you the other way as well. So know it that if I run and in here, let's just say hello head Enter. Now you can see it is showing hello for us. So now you know how you can download and install packages or libraries or modules and how you can use functions inside them in both ways. 60. 61 Create Function: No, it's time to talk about functions. First, why we need functions. Let's say we have a task that we do it a lot in our code over and over again. So that's the first reason that we can put it inside a function, a wrapper. So wherever we want to use it, we just put the name of that function in our code, and it will do everything for us. Next reason is for it to be more readable. So our code will be more compact and readable and categorized, right? So, for example, we did say hello word a lot in this course, right? So let's just create a function for it, so we can always use that. In here, what I want to do I want to create a new file, and I want to call it function one that PY. And in here, you remember we say print hello word a lot, right? So now, we want to create a function for it. And for creating a function, you always should say deaf or define after that, the name of functions, for example, say hello, that's it. Every function needs a open and close prenss and after that, a colon. After the colon, whatever code you put beneath the function, if it has four space indentation on it, it will be run whenever we try to use this function. For example, in here, I want to say print. And in here, let's just say hello W and we can have multiple line of code. For example, let's just say print and say from function, right? So this is our first function. And the important thing about Python is that Python will execute code from top to bottom. So first, this line will happen next this line, next this line. So this is really important to create your function at top of where you want to use it. Know with that done, I don't want to do anything. I want to just save and in here, run it. So we say PY, function one dot PY, and you can see, nothing is happening. Why nothing is happening. We have some code in here. Because we have a function, Python won't run it unless we tell it to run it where, for example, in here, we want to use that function. That's it with open and close parenss. Know it if we run, you can see it says hello word from function. No, in here, I can use it multiple times. So again, I can say that hello word and in here, run, and now you can see this function caused these two lines of code to print hello word from function twice, and you can see it over here because we call the function twice, right? That's it. That's how we create a function and we use. 61. 62 Function with one input: Functions can have input as well. So let's see how we can use the input of a function. So in here, what I want to do, I want to create another function. So for doing that, I will say death, say hello to, right? This is a new function that you want to create. I need open and close prenss. And inside these prances, we can tell Python that this function needs an input, right? For example, I want to say hello to somebody, so I will put name there. Create a variable, whatever, it will be okay. After that, a column, know in here what I want to do. I want to use a print F string, right? And in here, I want to say hello. Calibraces and put the name there. That's it. Now, we have a function that has an input. For using it, I don't want to use this say hello. I want to use say hello to. Now with that done. If you create a open and close parenthesis, you can see in pop up, it says, put a input there, right? If you do it for say hello, what will happen, it says, put nothing there. That's it. And it is returning nothing. It will return none. So how you can read this the function doesn't need anything for input, and it won't return anything, right? But in here, if we put the open and close parents there, again, you can see it will tell us it needs an input and the name of input is name, and it doesn't return anything. We will talk about the functions that will return something, but for no, you can see it need an input that is called name, and it won't return anything. So in here, if I, for example, say, Max, let's see what will happen. I don't want to say hello. Control is to save. No, if we run you can see it says hello max. And if I use this function one more time and in here, say, David, what will happen? This is the input, and this input will be saved in name. And in this function, it will be used. Control is save, and in here, we can run, and you can see first, it says, Hello max, and after that, it will say hello, David, and you can see it how it works over here. Cool. Now you know how you can create a function that can take an input and use that input. 62. 63 Function input default value: We create a function that gets an input. But what if we don't put anything on its input? Let's see what will happen. In here, we did use say hello to, and if we just delete this and just use say hello to and don't put anything for input. Let's see what will happen. If we run, you can see, it's a say hello missing one required positional argument name. So if the function needs an input, we should provide it, and we can't pass an empty in there. So when we want to create a function that if they put an input, it should work. And if they didn't put the input as well, it should work as well. So it will be more bug free, right? So for doing that, we can decide a default value for input function. So in here, we can just say name is equal to something, for example, an empty string, right? Just like that. No, if we run, you can see it will just just say hello. We can put whatever we want in there, for example, Max by default. And know if we run, what will happen because we didn't put anything inside it, the default value will be there will be inside the name, and it will say hello, Max. But if you put something inside it, for example, David, now let's see what will happen. Control is to save and in here run, you can see it will say hello, David, because this name is equal to Mx, it's just a default value that we put in there. So if the user that want to use this function, don't put anything as input, it won't give us any error. That's 63. 64 Function with more than one input: Create a function that has one input. Let's see how we can create a function that has more than one input because we can do that. So for doing that, let me delete this. We create two function. I want to create another function. For example, I will say death. After that, the name of the function, I want to call it sum, right? After that, open and close prances. And in here, I want to show sum of two value, right? So as an input, I can put two variable there, for example, A and B. Just like that, with a colon, we can write or code. For example, we can say, C is equal A, plus B. And after that, we want to show that. We say print C or we can use FS string. So for example, in here, we say F, after that, double quotation mark, and in here, we want to save some of open and close curly bracket, A, and another curly bracket, B is another curly bracket, C, right? So now with that, let's just see how we can use this function. We say sum, and we want to use it. As you can see, it says it needs to input, A, it can be anything, and B, it can be anything as well, and it won't return anything. So if you put two and three in there, it will sum up these two value, and it will show the result for us. Now, let's just run. You can see it a sum of two ent is five. If you change these values to five, and eight. Let's see what will happen, control S and run. You can see sum of five and eight is 13, right? Now, we know how we can create a function that has multiple input. It can have more than that. For example, in here, I can say another input, let's just say F, right? So now it has three input, and we want to sum of all of these three input, just like that. C is equal A plus B plus F, and we can change stuff in here. You can see, and F is C, right? And in here, if you run, it will give us a error. It says, missing one required positional argument, F. So it says, you did put A there, you put B there as well, but you didn't put F. So if you put F, for example, let's just say two. Now, let's see what will happen. Control S, and know in here, if you run, you can see sum of five and eight and two is 15. Everything works fine. So now we know how we can create a function that has more than one input. 64. 65 Advance way of passing input to a function: No, I want to show you a better way of using inputs of a function. So, let's see. In here, I want to delete this. I want to create a function, so I will say div and I want to call it say hello fool. Right and open and close prances like always. Full, I mean first name and last name. So I will say first input is first name and second input, I will say last name, right? And a col and after that, no, we can write or code. We can say print. I want to use Fstrem. So in here, I will say hello to open and close curly braces, the first name, and after that, space, and after that, another curly braces, last name, right? A easy one. No, we want to call it. We have some way to call it. We can say say hello fool, and in here, we can pass, for example, Max. And for the next input, we can say Tin, for example, Max Tin, right? Now, with that done, let's just run. You can see it says hello to Max Tin, right? No, another way to use this input is like this. For example, say, first name is equal, to Max. Okay? And last name is equal to TIM, right? Just like that control is, it will be exactly the same like before. But this way of using it, you will see it a lot in team works, and it's really easy to work with. And the good thing about it is that you don't need to put them in order. So what I can do in here, I can just say, last name is equal to TIM, right. And after that, pass the first name. We say first name is equal to Max. It should exactly work like before. So let's just run hello to Max team. You can see with this type of calling a function, it's much easier to work with a team, and it will prevent lots of bugs. So this was another way of using a function. 65. 66 Function return: Till now, we had some functions that can take an input. But we didn't talk about how we can return some stuff. Let's see how we can do that in this video. In here, I want to delete this. I want to create another function. For example, let's just say death, sum of two number, right? And for the inputs, I will say num one and num two, right? Just with that, we need a colon. And in here, first way is to just show it, right? We can just say show the num one plus num two. That's it. It will show it to us. Now, let's just test that. Say sum of two number, for example, two and three. What will happen control is to save in here if you run, it says five, right? That's it. But I don't want to print anything inside this function. I wanted to be able to return it. So in here, we say return num one plus num. Two, that's it. Now this function. When we use it, it will return something and we can save it somewhere inside the variable, right? With this, if we use it, say sum of two number open and close parenss now you can see there is two input in here, num one, num two, and as a return, there is any. It can return anything, right? So it's not none, so we know that it will return something, right? So no, let's just test that out. For example, num one, we want to say it is equal to two, and num two is equal to five, for example, right? Now, what this will do if we hover over it, you can see it needs two input, and it will return something. So we can put it inside the variable. We say A is equal to sum of two number. No, we can show DA print. Hey, that's it. Now, we have a calculated variable that we can show it outside the function. Now, if we run, you can see it is giving us seven. That's cool, right? No, we did talk about all type of functions. 66. 67 Function practice: No, I want to give you some practices so you get more familiar with functions. And with this practice, I want to show you that you can do whatever that you want inside the function. You can have I in it, you can have for loop in it. You can have I loop in it. You can have lists in it. You can check the list. You can create a list. You can return a list. You can do all sorts of things. So for example, let's say we have a list of numbers and we want to check if there is an even number inside that list. So what I want you to do create a function that can take a list as its input and with a for loop, check if there is even number in it. If there is even number, return true. But if you check everything inside that list and there is no even number in after everything finished, return false. You try to do that. We'll do it in a second. So for doing that, I want to create a new file, and in here, I want to call it function two dot PY, right? So in here, first, we want to create our function. So for creating a function, we say DF or Dev. I want to call it has even number. Right, open and close parenss and as it's input, I want to get a list, right? So that's why I want to create a variable for its input, and let's just call it num list, right? And after that, a column and with some indentation. After that, in the next line, we will write our code. So in here, what I want, do I want to use a four loop and I want to check all the numbers inside our num list. Okay. And after that, a colon and in here, we want to check if the number percent or mod two is equal to zero or not. If it is equal to zero, we can return two, right? Because we know that there is an even number there because the num person two or mod two is equal to zero. Now, if we check all the numbers and we didn't return anything after the four loop. When the four loop is finished, we'll go to this line, and with just four indentation in here, I will say return false, right? That's it. No over function is ready, but let me explain it. We have a function that check a list if there is any event number inside it, right? And it will check it with a four loop. It will check all the items inside that list. And if M two of them was zero, it will return true. And when we return something, it's like breaking the function. It will get out of the function and it will return the result. And these return falls won't happen anymore because this return return will break the function completely, and it will return to the line that we use this function. Now with that done, let's just see how we can use this function. For example, I want to say, my list is equal to, for example, let's say, one, five, nine, seven, three, right? And this is our list. Now if we check D has even number. So let's just say has even number. It is a function, so it need a open closed parenthesis. And now you can see it needs numlist. And what I want to do in there on a pass or list there, my list, and the return is boolean, and we can save that inside somewhere. I will save it inside A, and let's just show it with a print. We say print A, right? That set control is to save in here, PY function, head tab, head tab one more time, so it will go to function two and head Enter. Now, you can see it did give us false why? Because first and first, it will put one inside the num one mod two will be one, so it won't be true and it won't return anything. So again, it will go back and check the next item. The next item is five. Again, five M two will give us one, so this won't be true and it won't return anything. So it will go to next item and next item. And because we don't have any event number, that's why this four loop will finish without returning anything, so it will go to the return falls at the end. No, I don't want to do it like this, put it inside a variable after that show it. I can just say print just like that wrap it around open and closed parenss that's it, I will give us the same result, right? Now, if I put, for example, a two in here, so no list has an even number inside it, right? So with that done, if we run, what will happen? I will give us true. Why? Because it will check one, five, nine, and none of them will return true. But when it's checking two, two, MT will give us zero, so it will return true, and it won't reach this line at all because it's returning and breaking the function. That's it. Now, we have a function that we can use it to check if there is an even number inside our list. No, I want to give you another challenge. What I want you to do, I want to create a function that get all the even number that is inside a list and put it inside another list and return that list. You try to do that. We will do it in next fiddle. 67. 68 get all even number from list: No, we want to create a function that will get a list, and it will get all the event number from that list, and it will return. So for doing that, what I want to do, I want to just delete this part. I want to create a function in here. It exactly like this one, so we can copy and paste some part of it, but I want to do it from scratch, so you will understand it better, and I will explain a one more time. In here, for creating function, I will say DF or D for creating a function, and I want to call it get or even numbers, right? This is the name of function. I need open and closed prenss and the name the input variable, again, I want to call it num list. It's okay, right? And after that, colon and after that, let's just create or logic. For every number in our num list, right, we want to check if num person two is equal to zero or not. If it is equal to zero, what we want to do, we want to create a list and add this number to that list so we can return it at the end. So for doing that, we need to create a placeholder variable. So in here, I want to call this variable or even number list. Okay? And what I want to do I want to equal it to a empty list. That's it. Now with that done. If the number person two is equal to zero, we can add it to this list that is empty right now. We say all event number list dot append. With this append method or function that is inside a list library, we can add numbers or items to a list. So in here, we want to add the num, right? So if the number person two is equal to zero, we will add it to all even number list, right? And at the end of this function, when these four loop get to be finished completely, we can return the all even number list. And that's it. This is our function. Now, in here, we have this list that has just one even number. Let's just add more, for example, eight. After that, nine, after that, let's just say six. Now we have three even number. Let's just see if our function is working fine or not? The name is get all even numbers, and we pass the list. It's called my list, and what it will return, it will return. If you hover over it, you can see it is returning a list. We can say that inside a variable, but we don't need to. We can just print a tot, right? So just like that, we are printing it out. Control is to save. Now if you run, you can see it is getting all the event number, it will put it inside a list, and it will show it to us 286. Cool, right? Now if you add more, for example, 12, 25, 89, 36, 48. And just like that, control is to save and run. Now, you can see it is giving us all the event number as a list. 68. 69 function return more than one variable: I want to show you a way that you can return more than one thing with a function. Let's see how we can do that. In here, I want to create a new file, and I want to call it function dot PY, right. And with that done, I want to create a function, and I want to call it, for example, get Ale info, right? So this function needs open and closed parenths, and with that, we need the column and now we can return the Als info, right? I will give you more practical example after this. But I want to show you the basics first so you will understand it. After that, we will go through more complex stuff, right? Let's say the name of Alice is Alice, right? That's it. Now, the age of Alice creates a variable, and it's equal to 30. And let's say the country that Alice is in is a string, so we can save USA, right? So we have some information about Ale, and we want to return these informations that maybe we get from Internet or wherever. We did hardcode it in here, but in future, we get it from Internet, for example. And now we want to return this stuff. So we say return name and age and country. So return all the information about the Ae back, right? So now, let's see how we can use. We say get Alice info, right? That's it. This is a function. And what it will return us, you can see, it is returning us a topple, right? So we can use topple unpacking to save the information that these functions gives us, right? So in here for saving it, we say Alice name, and Alice H and Alice count tree, right, is equal to the informations that these functions gives us, that is a topple. So what we are doing in here, we are unpacking the data from return of this function. How we can use topple unpacking in here because when we return multiple stuff, Hiton will make it inside a topple and it will show it to us, right? So for you to see it better, first, let me show it just like this print. And use the FS string. I want to say curly brackets, show the Allie's name. After that, I want to say has another curly brackets, show the Allie's age. Years old, for example, and she lives in another car bracket and show the Alice country, right? With that control is to save, I want to say PY function, head tab, time, head inter. No, you can see Alice has 30-years-old, and she lives in USA. So you can see, we did unpack it. But what if we did use this function in here and use a print on it, just like that. We are not unpacking it, right? So what this will give us if we run it will give us topple of all the information about As, right? So now we know whenever we are returning multiple stuff, Python automatically put it inside a topple and it will return it. And we can use topple unpacking to get the information that we need. 69. 70 Function tupple unpacking Practice: No, I want to give you more complex examples so you will understand the returning of a topple, right? So in here, I want to create a new file and I want to call it function for that PY, right? And in here, let's say from Internet, we are getting some stuff. For example, a list of topples, right? So in here, I want to call this user infos, right? Is equal to a list of topples. For example, I want to say the name is Alice, right. Another item inside this first topple that is inside this list. I want to show the age that is 30, right. After that, the country, let's just say USA, right? This is our first topple. Next topple, I want to say the name is Max. After that, the age is 45 and the country, let's just say U. You see, I'm using double quotation and single quotation inside one topple, so you will understand that we can use both of them, right? It's easy. Now, let's just add another one, another topple. Let's just say the name is David. After that, the age, let's just say 25. After that, the country, let's just say Egypt that's it. Control is to save. Now, let's say we did get all of these informations from Internet. Now, we want to create a function to find a person and get all of its information, right? So in here, I will say death, get user info, right? Open and close parentheses. And for its input, I want to put name in there, no in here. We want to use a for loop on these user infos, right? So we say for person, for example, you can call it whatever you want in user infos, right. So what this person will give us, it will give us a topple of a string, int and a string. You can see it will give us a topple and with that, we know that this person will be a topple of a string int and a string because you can see a string int a string. Python is smart in that way, right? So now we want to check if the name that user gives us is equal to one of these names, you can return that topple. So in here, I will say if person, and we want to get the name. The name is first input inside this topple so we put zero in there. We know that for sure. If it is equal to the name that is coming from the input of this function. In that case, you can return the person, right? And what this will do, it will return that person if it exists, right? So let's just see how we can use it. In here, I want to say get user info and inside it, I want to say, please give me the Max info. Put Max in there and know what this will give us. It will give us a topple of SDR int and SDR, a string integer, a string, right? Let's just save it inside for example, max info right. And with that, I want to show it. So with a print, we can show Max info, right? Just like that control is to save. We want to use PY function at tab three times. So we go to function four head inter. Now, you can see it is giving us max 45 UK, right? So we can use topple unpacking in here because we know that this function is giving us topple SDR in SDR, right? So for unpacking the topple, let's just say person name and person age. And after that person count t, right, is equal to the data that this function will give us, right? So we are unpacking the return of a topple inside some variables, right? So now, let's just use a print of a string in here to show it. In here, we say F, the quotation. First, I will add a curly bracket, show the person name, right? Person name has another curly bracket, person H. After that, I want to say yours old. And he or she lives in another curly bracket person country, right? Control as to safe. No, in here, if we run it says Max has 45-years-old, and he or she lives in UK, right? So now, if we change this Max to, for example, David, let's see what will happen. Control is safe and no Run, you can see it says David has 25-years-old, and he or she lives in Egypt, right? So everything is working fine. But what if we put some values there that we don't have it inside this list? For example, Tom, right? Control is to save. Now, if you run, what will happen, it will give us error. It says, cannot unpack nonterable non type object because it didn't return any topol, right? So that's why it gives us a error. So for fixing that, what we want to do after this four loop happening and it didn't return anything, we can do whatever we want. For example, we can return none, none and another none. So what this will do, it will return a tuple of none. So in here, if you run, it says none has none years old, and he or she lives in none, right? So it will return in none. But we don't want to show it like this, right? So what we can do, we can check one of them. So in here, we can check if person name was not equal to none. In that case, you can show all of this. So Control X to duplicate this, add for space indentation and Control V to paste it, right? Control to save no. If you run, you can see nothing has happened because the person name, because it is Tom and Tom doesn't exist, it will return none. So with that, we prevent printing something that it shouldn't be there. But in here, we can add else there. So in here, use an se after that colon and in here, you can say print person, is not there, right? That's it. Control S to safe. Now, if you run, it says person is not there because Tom is not there. So if we change this to Alice, let's see what it'll happen. Control E to save. If you run, it says Alice has 30-years-old, and he or she lives in USA. Now, we have some codes that it is working. 70. 71 Adding comments: Know that where functions and codes is getting more complex, we need to know about commenting. Let's see how we can add some comment. First, what is the comment? Comment is a line of strings that Python will ignore always, and we can explain things there, and it won't be executed at all. We can add it to wherever we want. So for example, in here, I want to add a comment on top of this. I will use hash tag, and after that, I can explain what this is. I can say this is a list of topples of users informations that we can get from Internet, right? That's it. This line is for just explaining what we have done in future. So in future, whenever we get back to our code, we know what we have done with this explanation. And after that, let's just add another one in here at hashtag. I will say, with this function, we get user info. After that, for example, at front of this four loop, I can add comment. So in here at the hashtag, I can see with this, we loop through all of the items inside user info's list, right? After that, in here, add another comment, I want to say, we check the user name, right? After that, in here, add another comment. If the user name was equal to the name on input, we return the user or person, right? And in here, I can add another comment either at top of it or in front of it, right? So in here, the indentation is not important for comments. So in here, we return none if we didn't find the user. That's it. Now, we add some comments that explain our function, and it's really good to always add comments. 71. 72 Limitless inputs args: Now, I want to show you another thing. We can have multiple input, but always we have a limitation. Let's see how we can pass this limitation. For doing that, I want to create a new file and I want to call it function. Five dot PY. So with this, we want to create a function that can have multiple input, but there is no limitation on how many input it can have. So for example, we want to create a function that say hello to everybody, right? So I will call it say hello to all and open and close prances. For input, we use star names, right? Star names. So what these star names do it will tell PyTon compiler that this function can have as many input as it want. And with this star, PyTon knows whatever we put as input, it converted to a topple and give it to us, right? So let's see how it works. A colon after that and in here, I want to use for loop and I want to say for name in names, right? And after that, a colon, we want to print F string. Hello to open and close curly bracket and use name there. Now, let's see how we can use it. For using it, let's just go here, go down a little bit, so it will be easier to read it. And in here, on say hello to all and open and close prenss, you can see it can have multiple names, how we can pass them. In here, we can add, for example, Max, after that, add another one, for example, David, and after that, pass another one, for example, Tom. And with that, control as to save in here, we want to say pi funk tab multiple times. So we reach function five dot PY head Inter. No, you can see it says hello to Max, hello to David, hello to Tom, and we can add more input to here, right? For example, let's just say Navi it, right? And in here, let's just run and you can see, no, it's saying hello to Max, David, Tom, and Navid, right? Cool. Now let's see another thing. For example, we have a function that can add numbers, right? We did this before. We add numbers together. We create an input for just A and B, at some point, we add C and D to it. But no, we want to use this star for telling Python that whatever number they put as input, add them together. So in here, we can say star numbers, right? So you can add how many numbers that you want, and these function should add them together, right? This is a challenge for you. Try to create this function yourself and test it, and we will do it in a second. So for doing that, I want to first create a variable. I want to call it total is equal to zero at the beginning. After that, we use a four loop on numbers, number in numbers, and a column after that. And we want to say total is equal to total plus number, right? Number itself. That's it. Now, after that, when this four loop finished, it will go to this line. Just four space indentation, right, as same line as this four loop. So when the four loop is finished, it will go to this line. Either we can return it or print it, right? We can say return total, or we can just print it. We say print. And with the FS string, we say total is open and close curly brackets and show the total, right? Now, with that done, let's just go and use this function. For using this function, I will call it add numbers, and let's just add some number. One, two, three, four, five. It doesn't matter how many you want. You can add there. There is no limitation, no let's just run, and you can see it says 36. If I change this, for example, to one, two, three, again, it should give us the result, please run, and you can see it is six, and it is correct. So this way of passing inputs with a star, it helps us to create functions that there is no limitation of the number of inputs that it can take. But one other thing that I want to show you in here is that when we pass these numbers, what Python do with them? If, for example, in here, just print the names, right? Just the names, right? Let's see what will happen. Control to save. Now if we run you can see it is giving us a topple of all of the inputs. That's why four loop is working on it. And again, for these numbers, again, we can print the numbers, and you will see that it's returning topples. And that's why we can use four loop on it and do whatever we want with it. You can see it's just a top 72. 73 limitless inputs with kwargs: No, I want to show you another way that you can pass as many input as you want inside the function with a clearer way, right? Cleaner way. So for doing that, let's just create a new file. I want to call it function six dot PY. Right? And in here, I want to create a function, and I want to say print user info, right. And with that, we need to specify a input, right? But this time in one star, I want to use to a star. And with two a star, we tell Python that the inputs is limitless and they can add as many input as they want. And I need it in a key value pair way, right? So let's just name it user or whatever you want to call it. After that, a colon. And in here, first thing first, let's just use a print to show the user, right, to see what it is giving us, what Python gives us. And now, let's just use it. Print user info and for the inputs. No, it has two star right. So what we can do, we can say name is equal to Alice, right. After that, we can say, for example, age is equal to 35, for example. After that, we can say country is equal to USA, right? So we are passing some stuff there. And Python what we'll do, it will convert all of these to a dictionary, right? Let me show it to you. In here, if I say PY, function, a tab, sometimes, so we reach the function six, head inter, and now you can see, it's giving us a key value pair of a dictionary, right? So with this user, it is just a dictionary, and we can convert it to a topple and after that, unpack it and use it, right? So for doing that, what I want to do I want to use a four, and in here, I want to say, we have a key and we have a value inside user dot items, right? Just like that. And know with that what we can do, we can print everything. So we say print. Use a FS string. We say curly bracket, key. Is, for example, another curly bracket and show the value, right? That's it. Control Save. Now, if you run, you can see the name is Alice, age is 35, country is USA. And if we add more things to it, for example, if I add height is equal to 173, right? Control TSAve and run it in here. Now, you can see it says name is Alice, age is 35, country is USA, and height is 173, right? We can add more. So for example, let's just add weight as well. Weight is equal to 58, right? Control is the safe. And now you can see, we can access that. So with these two star in there, what it will happen, it will convert all the key value pair that we pass as input of a function to a dictionary, and we can use that item on it so we can change it to a topple and we unpack it like this, and we use the data inside it to show all the information about a user. That's 73. 74 using both args and kwargs in one function: No with that done, we can have both one star and two star input both together. Let me explain. In here, let me create a new file. I will call it function seven dot PY, right? And in here, I want to do both of things that we done in here inside here, right? So what we can do, for example, we want to print user info. So for doing that, let's just copy all of these to here. This is our function that is getting a key value per input, limitless key value per in input. Now, I want to add workover as well. So in here, I want to see how many our she or he works in a day, right? So for example, I can add a star, and I can call it hours, right? That's it. Now with that done, we are showing the information about that user in here, and now in the next line, I want to use another for loop hour in hours, right? What do you want to do we want to have a total over in here at top, so we say total ho and it is equal to zero. And now we want to say total over is equal to total over plus hour, right? When I give you an example, you will understand it better. So in here, at the end, when both of these four loop get to be finished, I can print the total O. And in here, let's just use the FS ring. I want to say total O is curly bracket and show the total ho there. Now with that do, let's see how we can use it. Go to the next line and in here, use print user info, and in here. The important things, you see, first, we should put the hours there and after that, user info. So in here, let's see, she works like two hour first day, three hour next day, eight hour next day, and four hour next day. And after that, we give the name. Name is equal to Ale. Okay. And we want to say company position. Is equal to CO, for example, right? And let's just say salary is equal to 100,000 just like that. Know what Python will do. It will convert all of this number at beginnings that is not a key value pair inside these s as a topple, and it will put all of these key value pairs and convert it to a dictionary, and it will put it inside the user variables, user input, right? Now with that done, control is to save. And in here, if we run the PY, function seven. Let's just go to function seven, head inter. Now, you can see the name is Alice, company position is CO, salary is 100,000, cool. Total hour is 17. We did use both of one star and two star or arcs and Kw arcs inside just one function. That's it. 74. 76 Map: Now, I want to show you how you can use maps. There is a map function inside Python that we can use to do one function on a list items of that list. Let me show you an example. You will understand it better. In here, I want to create a new file and I will call it map dot PY, right? So in here, let's say we have a function that convert lower as to upper Ks, right? Really long name. And in there, we have a string. I will call it MSTR, right, or whatever. After that colon. And in here, we can return the mystr dot upper, right? This is a method or a function that we can do it with a string, right? And know with this function, let's just give it something. For example, convert, lowercase to uppercase and in here, give it a string. For example, let's just say max. And what this will give us if we hover over it, you can see it is returned something for us, so we can save it inside something. We can say A is equal to whatever that this function return. And no if you print it, let's see what will happen. A, print A. That's it. Control S to save in here. I want to say PY, map, tet inter. No, you can see. We did give it max in lower case, but it did give us max in upper case. But no, let's say we have a list of names that we want to convert. So in here, let's just create a list. I will call it my names is equal to a list of names. For example, Max, after that, David, and after that, Tom, and so on, right? Now, one way to do it, we can just create a function, loop through everything and do this upper method on all of them, but there is the fastest way to do it, and it's called map. This map gets a function that in this case, we want to pass the convert lowercase to uppercase, right? And without any open and close parentheses, we need to give it the list. Or list is my names, right? What this will do, it will get all the item one by one from this list and pass the item as input of this function, and it will do for all of them, and it will return something for us, right? It will return a map for us. We can't show a map with a print. That's why I want to use a list function in here to convert this map to a list. And this list, we can save it inside somewhere. For example, inside a variable, right? Now, if you print what will happen, print A, control is to save and no run, you can see it did give us a list of all the names, but it is in uppercase, right? No. You know how map is working. Get in all the items and put it as input of the function that we provided there and give us a result in map, and we convert it to a list, and now we can show it, right? That's it. 75. 77 Filter: Like we have a map, we have a filter as well. Let me show you an example. If I create a new file, I will call it filter dot PY. And in here, let's say we have a list of numbers and we want to check which one of them is even number, right? We can do it with a four loop and with a function, and you know how to do it we done it in this course. But I want to show you how you can use filter for doing that, right? So for doing that, let's just create a function Dev is even. Right? And this function gets an input, for example, num or number or whatever you want to call it. After that colon, we check if number person two was equal to zero after that colon. And in here, we can just say return true, right? Just with that, if a number is even, this function will give us a true. So let's just test that out. In here, we can use a print and use is even function in it, and let's just pass a number. For example, two, two is even, so it should give us true. So we say PY, filter, head tap, head inter. No, you can see it did give us true. If we put five in there, what will happen? I will give us none, and you can see it over here. Why giving us none because at the end we didn't return falls. So in here, we can have an s. If it's not equal to zero, we can return false, right? That's it. No, if we check that out, you can see, no, it's giving us false. If we put a tender, what will happen, it should give us two because it is a even number, and you can see it did give us two. But we have this function and we have a list of numbers, and we want to check each one of them if it is even number or not. One way is to use for loop, right? But I want to show you filter. So in here, we say filter, and inside it. We want to check the function is even on a list. So let's just create a list as well in here. I will call it my nums numbers, right, is equal to a list. For example, one, two, three, four, five, six, seven, eight, nine, and ten, right? This is our list, and we can pass it in here, my numbers. So what this filter do, it will check all of the numbers inside that list, and it will put those numbers as input of this function is even. Inside this number, and it will check everything, and it will give us on each one of them either true or false. If it's even, it will give us true. And if it's not even, it will give us false, right? But this filter is giving us a filter as well, right? So that's why print can't show it, and that's why I want to convert it to a list in here. I say list. So open and close prances over here, right? Just like that. No, we can save it inside the variable. Let's just say A is equal to this. No, let's just show DA, print A. Control S to save. Now, if you run or code, it is a list of two, four, six, eight, ten. So it did get all the numbers one by one, check it with this is event function. And if it was true, it did return it to us and we did convert it to a list, so we can show it and you can see it over here, right? So that is how filter works. And for beginners, you don't need to use this a lot. It's better not to use it at all. I want you to be able to read others code. There is more readable way to do this kind of stuff, and you know that with a four loop, right? That's set for filter. 76. 78 Lambda expresion: Did learn how to create a function multiple ways, but I want to show you a new thing how you can create a function with Lambda expressions. I don't recommend to use Lambda expressions too much because it makes or code not that much readable, but you need to know about it as well. So without explaining it. Let me give you an example in here. Create a file in here. I want to call it lambda dot PY, right? So in here, let's say we have a function that whatever value we give it, it will return its square two, right? For example, let's just say Div. Let's just call it number, square, and it gets a number from input. So let's just put a number variable there after that the colon. And in here, we just return Number square by two, right? What this will give us, let's just test it. In here, I want to use it. Use number square function in here, let's just pass two and what it will give us, it will give us a number. We can save it inside A, and let's just show it. We say print. A, that set control is to save. Now in here PY, lamb head tab, and it will put the rest for you, head inter, you can see it is giving us four, right? If we put four in here four by four, let's just see what will happen. It will give us 16, right? So we have these functions and it's readable, right? But I want to change it. I want to convert it to a amta expression. Let me delete this. How I can do that, I can say Lambta first, after um Do key in here, we need to tell it the input. In here, we had the number input. So in here, we can say number, right? So this is the input of the um do expression or Lambda function. It is um do expression, but I will call it um do function so you will understand it better. So when you say Lambda, it's like you are saying death that you want to create a function, right? This is the input of that function that in a function, we put it in prances, but in here, we don't need to do that. After Lambda, we can define the inputs. And after that a colon and in that exact line, you don't need to go to the next line, you can write whatever you want to return. For example, number square two. That's it. So this function is exactly this function that we have in here, right? H, this is like the depth that we have in here. This is the input that we have over here, and this is the return value that we have over here. But we don't need to tell it to return it. It knows because it is at the right side of this colon, I need to return the result of this and it know the variable at the left side of this colon is the input of our function, right? Know how we can use this um do expression. This umd expression, it will create a umd expression as well that you can save it somewhere. For example, let's just call it num square, right? Equal to this, right? Now with that done, let's just see how we can use it. We say num Square. After that, we give it an input. For example, let's just put two in there and know it is returning a value for us. We can say that somewhere. Let's just say A is equal to num squared two, and let's just show it. Print A. Control is to save. Now if you run it, you can see it is giving us four. The difference between these two is that, with Lambda expression, or code will be just in one line. We don't need to define a function like this, have indentation, have two line of code. We can just do it in one line. Create a Lambda function or Lambda expression in just one line, and you can see it or here. Now, with that done, let me give you another example. For example, we have a function that at two number, right, add two number. And for inputs, we have A and B, right? After that, colon, and we are returning A plus B. And that's it. This is our function. Let's just go to next line and use it. We say, add two number. Let's just add two and three. No, let's just save it inside the variable. Let's just say A is equal, add two number, and after that, let's just use a print to show it, show the A, control is to save. Now, if we run, it will give us five because two plus three is five, right? This is one way to do it, but we know we want to do it with Lambda expression. For doing it with the Lambda expression, we say Lambda. After that, the input the input is A and B, so we say A and B. After that, we need to add a colon and Lambda or Python knows that when we say um Da, after that, we have a colon. At the left side of that colon, we are defining the variables and the right side of it, we tell it what to return. We want to return A plus B, right? And now for using that, we can save this Lambda expression inside the variable. Let's just call it sum of two number, is equal to this Lambda expression. Now, let's just see how we can use it. We say sum of two number, we pass two number A and B, for example, two and three, and it will return something for us. We can save it inside, for example, a variable, right? And let's just show that. We say print, A, that set control is to save. Now if you run, you can see it is doing exactly what this function is doing. But the cool thing about Lambda expressions is that you can use them with a map and filter function. Let's see how we can do that in next. 77. 79 Lambda expresion with map: Now let's see how we can use Lambda expression inside a map. First, let me find the map in here. So with the map, what we have done, we create a function and we pass the name of that function to the map, and we give it a list of text in this example, and we make all of them in upper case, right? And we pass that list at the second input of this map function. After that, we convert it to a list, so we can show it. Let's see how we can do the same with Lambda expression, right? For doing that, I want to copy all of this and I want to create a new file. I want to call this one map, um dot PY. And know with this control V to paste all of this code, right? Now with that done, I don't want to use this function. What I want to do, I want to create um Do expression to use instead of this function that we have in here. So let's see how we can do that. We say Lambda, after that, we need the input. So let's just pass my STR. This is our input. And after that, a colon at the right side of that colon, we return whatever we want. We do whatever we want with this input, and we return it. We don't need this return key at all, it will return it automatically. So we say my SDR dot upper, right? Just like that. No, we need to save this Lom Da expression inside a variable so we can use it over here, right? No, with that done, let me save it inside. Two upper, for example, right? It's equal to this Lambda expression. Now, instead of using this function, we can just delete that function. We don't need it. We can use this two upper Lambda expression and put it over here. Just like that, if we run no, say PY map, Lambda, head inter? No, you can see all of the items inside we list converted to upper case. So you may say, why we need to use this Lambda expression. The function is more readable. The reason that we use it it's because we can do it in one line. We don't need to just save it inside the variable. We can just copy this and paste it over here. That's it. So we create our Lambda expression inside over map, and it will do the job for us. If I just delete this, just like that, just delete that. Now with that done. If we run, again, it will give us the same result because Lambda expression we can just use it inside the map. That's it. But I don't recommend to use it because it is not that readable to have something like this, but I will explain it one more time. When you see Lambda, it means we want to create a Lambda expression, a function in type of Lambda expression, right? Now after this um keyword, we have a column. At the left side of this column, we have the variables, inputs of our function, and at the right side of this column, we have all the calculations or things that you want to do with that input. And when we put it at the right side of this column, it will return it automatically. So what it is doing in here, this map function. Gets all of these items one by one and put them inside this MSTR. And because at the right side of this expression, we have dot upper. It will make everything to uppercase, and it will do it for all of these items, and it will return it as a map. We change it to a list, and now we can show it and you can see the result. We can do it for the filters exactly the same use Lamda expression. Let's see how we can do that. Next. 78. 80 Lambda expresion with filter: Let's just do the filter much faster. In here, let's just create a file. I want to call it filter Lambda dot PY. And I here, if you remember, we have a filter. So let's just copy all of these and put it inside filter Lambda. We want to convert this function to Lambda expression, right? We have a list of numbers that we want to filter just the event numbers, right? For doing that, let's just say Lambda. And after that, the inputs in here, we had number. Let's just call this one num. After that, a colon, no, we want to return something. We can just return this equation in here. We say num, percent two is equal to zero. Now, what this will do this is input function, and this is what we are returning. If you put one for input, one person two, it will give us one because it is not equal to zero, I will return false, right? So this will return false. If you put inside this num two person two will be zero. So this will return true, right? Now with that um do expression, we can just put it inside a variable, for example, check even. It's equal to this um do expression. And now with that, we can just delete this. We don't need it. Just like that. And instead of this is even, we can use heck even this time, right? That is Lambda expression. Now, in here, let's just say pipe, filter, headter No, you can see it is giving us all the even numbers. Of course, we don't need to put this inside the variable. We can just delete this and use this Lambda expression directly in here. That's it. Control save. Now, if we run again, it will give us the same result. And again, the reason that we are using Lambda expressions is because it's more cleaner for pro users, right? So this kind of one line codes. It's more cleaner to use Lambda expressions. But my recommendation is to use functions. This is exactly a function that is just in one line. That's it. Now, you know about filter with Lambda expressions. 79. 81 Variable scope: In this do, I want to talk about variable scope, and this is really important. So let's begin. In here, I want to create a new file. I will call it variable scope dot PY. And in here, let's create a variable. For example, name is equal max, right? No, we have access to this variable and the lines beneath it. So we can print it, right? We can say print name, right? Control is to save. Now, in here, PY, variable scope. We can see we have access to Max. That's why we can use it, right? But what if we cut this and put it after this print? What will happen? First, we say print name, and after that, we declare the name. It's obvious, right? It should give us error. But see, can see it says the name name is not defined. So for you to access variable, variable should be first declared somewhere so you can use it, right? No. What about a function? So let's say in here, we have a function def, say hello. And just like that, we want to print Hello, read FS string. Hello to open and close curly brackets and put name there. In this case, this variable is a global variable, and we can access it in all the functions and we can use it. Now if you use this function, say hello, what will happen? It will print hello to Max. You can see hello to max, right? Now, let's say we want to declare this not above in here, we want to declare it in here. You see, after this function. Control is the save and know if you run, you can see, again, it can find the variable name and it is using it. Now if you cut this and put it after this function and run, again, you will see that it says name is not defined. Why? Because this function we'll call first, and after that, we are declaring the name. So this name, we can't use it inside that function. It needs to be there in here, or it needs to be in here at top of everything. So no with that we have access to the name. And if we run again, it should show hello to Max. No, next thing. Let's say we want to declare the same variable inside this function. We want to say name is equal to David, for example, right? Now with that, Don, if we run what will happen, I will say hello to David. What just happened? When we want to use a variable inside the function, Python will first check. If that variable exists inside that function, it will use that variable that is inside that function. But if it doesn't exist in that function, it will reach in global space in our code, and it will get that variable and use it. And know because we are declaring the name inside that function, that's why it will print Hello to David. But what if we use print and print the name outside of this function? What will happen if we run, you can see first, it says, Hello to David because in this function we did declare the name variable to be David, and we use that in here because it is inside the function. That's why it tried to find that variable first inside that function. And because it is there, it won't go to this one, right? But when we say print name in here outside of this function, this print see the variable that is in global space, right? This name is equaled David is called local variable to this function, and this name is equal to max is a global variable that we can access it beneath that code wherever we want, right? So this is a global variable. And this is a local variable to this function. And let's say we delete this, what will happen in here, right? So we have a function. We did declare a variable inside this function. We call it David, and we did use it and it should work fine. After that, in a global space, we want to use that variable, but we can't. If we try to run this it will give us an error. It says, name is not defined. But before that, it says hello to David. So it will run this properly. But because this variable is a local variable to this function, we don't have access to it in a global space. So now you know, if you declare a variable inside the function, it will be local to that function and you won't have access to it outside of that function. But if you declare a variable outside the function at top of everything, you have access to it everywhere. Now, let me show you another thing. Let's say we declare a variable. For example, again, name is equal max, right. And with that, we want to be able to change this name variable inside the function. Let's see how we can do that. For changing this name variable inside this function, first, we need to tell it that it is a global variable. And how we can do that, we say global name and with this global name, Python knows even though this variable is defined, it's setting inside the function, it knows it should change it in global space as well, because we say global name. So with that, what this print hello to name do, it should say hello to David. And because we set global name the name in global space will be changed to David as well. So in here in global space, when we say print name, it should says David because we declare the name that is global, right? Now, if you run, you can see it says, Hello to David inside this function and outside of this function because we did declare it global and we set it after that. That's why the global variable name will change. And that's why we say print name in global space, it will return David. That's it about the variable scope.