Transcripts
1. Introduction: Hello and welcome
to the complete by three data structures
masterclass. This class is fully updated
with hands-on learning to help guide you from 0 to heal
and Python data structures. Python has four built-in
data structures. They are lists, tuples,
sets, and dictionaries. If you're learning Python, it's very crucial to learn those and the differences
in between them. Luckily for you, this
class does just that. In only 30 minutes
of video lectures, you will learn all those
different data structures, the differences between them, how and when to use them. This course is beginner friendly and straight to
the point that you waste less time in theory and more time in
hands-on experience. By the end of this course, you will have mastered
the fundamentals of those four built-in
data structures. And you will be able
to recognize them when reading someone
else's Python code. And if that's not enough
to top it all off, we will have an
interactive exercise as our class project, where we will quickly
recap the fundamentals of those data structures
to make sure that we have a deeper
understanding of them. So what are you waiting for? Enroll today and elevate your
Python programming skills. I'll see you inside the course.
2. Lists in Python 3: Hello and welcome
back to my video. Today we would be taking
a look at lists that are four built-in data types in
Python use to store data. They are lists, tuples,
sets, and dictionaries. We will start by learning lists, which are used to store multiple items in
a single variable. So let's start by creating a simple list called
cars for example. And now let's print our list. As you can see, it looks
exactly like our list, including the square brackets, we can print individual items
in our list using index. So for example, if I
want to print Toyota, I would do the following. Similarly, if I want to access the second
element in my list, which happens to be Volkswagen, I have to sit my index to one. Remember, lists start with 0. Okay, so let's say I want to access the last
element in my list, which in this case
happens to be Mercedes. And I don't feel like counting how many elements
are in my list. I could do that simply by
setting my index two minus one and minus two for Honda, and so on and so forth. Let's say for example, I want to print all
the elements in my list starting from four. I could do that by simply using colon to select a
range of items. So what if I don't want
to print items starting from two all the way to the end. Let's say we want to
set a start and an end. We could do that with colon two. So we will start from two
and we will end at four. So this will start from
two, which is four. Remember, because our
list starts counting from 0 all the way to four, which is Mercedes,
but there is a catch, it wouldn't print Mercedes. So when we set an enter colon, it ends at that element itself, but it doesn't include
it in our list. You can also modify a certain
item and you're less than. So. For example, if I wanted
to change Volkswagen, BMW, I could do that
by using index. Keep in mind, our list
could include strings, integers, booleans, you name
it all at the same time. So for example. Okay, so that's it
for the basics. Let's say we want to
write a program to find the largest number
on the following list. There are plenty of
ways to do that, and we're gonna go
through some of them. The first method is resorting our list in
an ascending order. I'm printing the last element in the list using minus one. So we will sort our
list using salt method. And now our list is sorted from smallest all the way to the
largest number at the end. Now we will print the
last element in our list, which should be the
largest number. The second method is max, slightly easier and
very straightforward. So this is how we use it. Those are two fairly easy
and straightforward methods, has slightly more
complex method is using for loops
and if statements. To do that, we will do the
following three steps. Create a variable and assign it to the first element
in our list. Iterate through
the numbers list, or in other words,
loop through the list. If any number is bigger than the largest number
we found so far, it should be updated. So let's create a
variable and assign it to the first
element in our list. Now, let's create a for loop that iterates over
each item in our list. Now, let's create an if
statement that checks if a number is bigger than the largest number
variable that we created. If that's the case, then technically this new number is the new biggest
number we found. Thus, we should
do the following. Now, when our loop
is done and it went through all the
elements in our list, largest number, should we update it to the biggest
number in our list? Thus, we should print this
number as the largest. So let's run our program,
see how it looks like. That's it for today's video. Thank you so much for watching and I hope to
see you in the next one.
3. List Methods: Hello and welcome
back to my video. Today we'll be taking a
look at list methods. The first method
we're going to be taking a look at is insert. So say we have the
following list. I want to add an
item to this list. For that, I will use insert. So this is how we will use it. This insert method
takes two arguments. The first argument is where
we want to place our item. So let's say we want to
place it after China, which is going to be two. Because remember United
States as add 0, China is at one. So our new item is
gonna be at two. So now we set the position. Now after the comma
will enter whatever we want to insert two on
our list. For example. Now let's print our list
and see how it looks like. So let's say you want to add an item at the end of your list and you don't want to
go through the hassle of counting how many
elements you have. You could do that using a bend. Bend only takes one argument. That is the element you
want to add to the list, because the position
is already determined, we can also remove an item from our list using remove method. Remove also takes one argument. We could remove the last item in our list using pop method. If we want to remove all
the items in our list, we can use clear method. This method also
takes no arguments. If we want to know the position
of an item in our list, we can use index. This can also be
used to check for the existence of an
item in our list. Let's try Italy for example. Since we don't
have Italy and our less technically it
should return an error. But because it returns an error, it's not very recommended.
We could use this. Instead. This returns false, which is a Boolean value
we could work with. So if we have a numbered list, we could sort it using sort. This method takes no arguments. If we want to count
how many times an element occurred in our list, we could use count. Now we enter the elements
we want account, let's say two, for example. So with occurred three
times in our list. This method takes
only one argument. So we saw how we could sort our list in an ascending order, starting from the smallest
value to the largest value, we could reverse our
less to all sorted in descending order
using reverse. So now it goes from
the largest value all the way to the
smallest value. We can copy a list
using COBie method. So for example, this is countries and this
is countries too. Now, if any changes
happening to countries, it will not affect
countries too. So let's remove the last
element in our country is less. As you can see, they're not identical because
it's only COVID, whatever it was, but
it's not updating it. However, if I equal
countries to two countries. Now whatever changes happen to countries which
would also apply to countries to join
lists together, we could either use extent. This is extent, or we could simply make countries
equal countries one. Plus, I mean technically
this is not countries one, but it's just countries. Let's see. So both will give us
the same results. So now we're at the last
segment of the video. So assuming we were given this list which
includes a duplicate, Germany was mentioned
twice in I was asked to remove the
duplicates from my list. Of course, there are
plenty of solutions, but we're going to do
that using for loops. So first, we want to create an empty list to
store our items. Now we will create a
for loop that checks if those items are not in our list than store
them in our list. So let's take a look at
what this for loop does. It says for each
item in countries. So it's looping through
each item in countries. It says if country, which is this item is not
an duplicates, then add it. So this will add
the item contrary to our no duplicates list. Now you might say, okay, this would add this item, this item, this item, it will eventually add this item to because it will loop
through all the list. This wouldn't happen
because we said f country, which is the following item, is not in duplicate because
we've added it previously, it will not be added. Let's print our list and
see how it looks like. As you can see, our
loop works just fine. And it's added all the elements
except the duplicates. So it's essentially a copy of our list without
the duplicates. So that's it for today's video. Thank you so much for watching and I hope to see
you on the next one.
4. 2D Lists & Nested Loops: Hello and welcome
back to my video. Today we will be taking
a look at 2D lists. As the name suggests, they are 2D list, meaning they have two-dimensions instead of one dimensionless, in which all the elements
are stored in one row. So let's create a 2D list
and see how it looks like. So in this list, each row is a list of its own. And to access items
in this list, we will be using two square
brackets instead of one. So for example, if I'm
going to ax is number one, I'll do the following. Similarly, if I want to
access five, our set, my index to 11, meaning the second row
and the second column. And of course we all know
lists in Python starts with 0. So that's why this is
one instead of two. We could even create a
fourth row and have it as 0. It doesn't need to
be three items. Now, what if I want
to print this to the list using print right away? It doesn't seem right.
As you can see, we have brackets
all over the place. So let's use a for loop
to print this list. Well, this is still
not good enough. This is where nested
loops come in play. So let's add another
loop inside of our loop to iterate through each
item in this list. Now we have successfully
printed each item individually. So that's it for today's video. Thank you so much for watching and I hope to see
you on the next one.
5. Tuples: Hello and welcome
back to my video. Today we will be taking
a look at doubled. A tuple is a collection of Python objects that
cannot be changed. Doubles, like lists
are sequences. The major distinction between tuples and lists is that tuples, unlike lists, cannot be altered. Tuples use parenthesis, whereas lists use
square brackets. So this is how a
list looks like. This is how a tuple looks like. If I type names, dot, as you can see, I get plenty of options
because it's a list. However, if I type names to dot, I have only two options. That is count and index
because it's a tuple. So that's the main difference. We use parentheses to define them and they have less
options than lists. We could print individual
items though, just like lists. So for example, this will print the first
item in our tuple. However, if I try
to change that item like we usually do with
lists, I would get an error. Tuple object does not
support item assignment for that lists of more common and you're more
likely to use them. However, they have
their own users for locking the contents of your own traveled
so that you don't accidentally change
them later on. You can also like
tuples and this format. Just to make sure
it's really a tuple, we can do that by using type
up and let's print that. We learned that we cannot
add items to a tuple. However, we can add
tables together. So for example, now let's
print our new tuple. We can not tell you move
individual items in a tuple. However, we can delete
a tuple completely. Here are four built-in functions
we can use with tuples. Len function which returns four because we have four
items in our tuple. Max function which returns 90 because 90 is
the largest value on our main function, she turns 15 because
it's our minimum value. And finally, we can use double function to
convert our list. So that's it for today's video. Thank you so much for watching and I hope to see
you on the next one.
6. Sets & Mathematical Operations: Hello and welcome
back to my video. Today we will be
taking a look at sets. It's a very useful
data structure similar to lists and tuples. But the major differences
that sets cannot have multiple occurrences
of the same element, or in other words, duplicates. So let's take a look at
some applications for sets. So say we have the
following list which contains duplicates. We can remove those duplicates
by converting it to a set. So let's create a set
to store our values. Now let's print our set
and see how it looks like. As you can see, we use curly
brackets to define sets and they have not containing our duplicates from
the previous list. Similar to lists,
we get plenty of options like adding
or removing items. For example, we could remove
an item using the Move. However, if we tried
to remove an item that is not in our set,
we will get an error. That's why it's safer
to use this code. Because if we tried to
discard an item and our set that isn't there,
we won't get an error. We could add an item using
ad and so on and so forth. You can explore more options
when you type your set dot. And as you can see, there
are plenty of options. Sets shine with their mathematical
operation uses in Python. So let's take a look
at some of them. At first glance, this set of operation might
seem confusing, but really it boils
down to four sections. Those are the four sections
we'll be taking a look at. I made this table to visualize
those operations easier. So let's take a look at union. To find the union of two
sets we could either use. It will return a new set with
components from both sets. One answer to, however, elements will not be repeated. That sets components
are all one-of-a-kind. You could do this with
more than two sets, two. So the difference between using union and vertical
bar operator is that union will accept any
iterable as an argument. While vertical dash will only
accept sets as an argument. Otherwise, it will
attend an adult. So now let's take a
look at intersection. To find the intersection of
two sets, we either use. It returns a new set containing elements shared by the two sets. So because only 24 were shared
between these two sets, this is the only elements
we have returned, similar to the previous one. The difference between
using intersection or the AND operator is that the intersection will accept
any iterable as an argument. And the AND operator
will only accept sets as an argument
otherwise, to turn an adult. So now let's take a
look at difference to find the difference of
two sets we either use. It will return a
new set containing elements from set
one and set two, because 35 were
not answered two, those are the only
elements we have returned, similar to the previous one, the difference
between difference and the minus operators. That difference
accepts any terrible, but this only accepts
sets as an argument. So now let's take a look
at symmetric difference. The find the
symmetric difference between two sets we either use. It will return a new
set containing items from either set one or two, but not from the both sets. So set two has a
unique item of 79. It's not included in set to one. That's why it's added here. Same goes for set one. It includes a unique
element of 53. That's why it's also here. And finally, the difference between the symmetric
difference and the circumflex operator is that the symmetric difference can accept any iterable
as an argument. While the circumflex
operator will only accept sets as an argument, otherwise it will
return an error. So that's it for today's video. Thank you so much for watching and I hope to see
you on the next one.
7. Dictionaries: Hello and welcome
back to my video. Today we will be taking a look
at dictionaries in Python. Three dictionaries are used to store data values like a map, unlike other datatypes that told only a single
value as an element, dictionaries hold
a key value pair. Suppose we're
making a website to bless or doesn't
buy items online, similar to Amazon,
Let's begin by making a dictionary
to store our values. We have several key data, so let's list those. Now we'll create a dictionary. To create a dictionary, we will use a left
breast and to close it, we will use the right place. We use commas to
separate elements and quotation marks to define them
inside of our dictionary. Now, our dictionary
includes keys such as item, type, seller, year, and
so on and so forth. And we have values
such as phone, samsung, and take cells. So this is how our dictionary
would look like in a table. As you can see,
our dictionary can hold values varying
from strings, integers, double float values, and so on and so forth. We can verify that our dictionary order is indeed dictionary using
the type function. We can also create
a dictionary using the dict constructor.
For example. We can add additional
elements to all dictionary using brackets. Keep in mind you have to use quotes when you're adding items. However, in the
deck constructor, you don't have to use
quotes around the key name. So let's print our dictionary
and see how it looks like. Now we will take a
look at how we can access data in our dictionary to print the type from our
dictionary order to, we will do the following. However, if I enter
the key name that is not in my dictionary,
I will get an arrow. To prevent returning
a key error, we could either use
an operator or try. Let's start with n. So let's run our code and
see how it looks like. We could also handle a
key error using try. So the reason I'm using here or here, because if you remember, when I tried to
print the following, this is what the
error would get, a key error type of error. So that's why I'm telling my
program to accept key arrow. There's more stuff we could
do with dictionaries. So let's print the
directory for order two. Let's try the getMethod. But to see how it works, we could use now to use this getMethod
in our favor to find if we have a key name called
age in our dictionary, we could do the following. Now let's print check. Finally, let's learn how to print all the data
in our dictionary. We could simply do that
by using a for loop that iterates over all the
items in our dictionary. For example. For a more simpler way to
print our dictionary values, we could use the items method. So that's it for today's video. Thank you so much for watching and I hope to see
you on the next one.
Naser Jamal, Computer Engineer
