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Hi, everybody.

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I'm so happy that you're here with me, and today we're going to discuss further regarding object oriented

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programming in Python.

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In the previous video, we have seen an overview of what is an object and how can we create instances

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of an object.

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We had like a sketch of a car.

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And on top of that, we could create two types.

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Of course, this was only an overview look.

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And today we will start explaining each term before getting to the point where we can create actual

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objects like advanced objects.

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We will start explaining everything from zero from this lecture right now.

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And let's go over the list of terms that we are going to discuss in this lecture and also in the following

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lectures as well.

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So what's in our menu?

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What is a class and how to create one?

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We will discuss it in a few seconds right here below how to create an actual object.

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And then we'll learn what our properties of an object we will use a special method and also a special

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type of method that we haven't seen before called in it.

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OK, so look down to this thing as well and then we will talk.

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What is a self parameter of a property?

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These two are connected.

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Don't worry if it sounds a bit scary because as you know, you don't need any prior knowledge.

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Do all this.

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We're going to discuss it from zero.

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OK, and then we will learn what our object methods and how to use them.

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OK, also, after we'll explain all of these terms, we'll start building the car object that we have

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seen in previous lecture from zero in live coding examples as always.

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All right, so first of all, let's start with the third with the first bullet classes, OK, so what

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are classis?

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So we are all very familiar of how to declaring method's OK.

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So once we want to declare a method, we just use the Def Keywood and then afterwards we put the name

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of the method.

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Small letters underscores between each each word as the coding convention tells us.

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OK, so a class declaration happening in the very similar way, but this time we will have to use a

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Klasky word and then give the name of the class.

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All right.

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So this is how we create classes, but where classes fit in, in the hierarchy of PyCon, meaning,

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for example, we know that our methods.

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All right.

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And we can contain variables inside these methods and we can also manipulate variables inside these

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methods.

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But we know that a variable is inside a method.

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OK, so method contains a variable.

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It can contain a variable.

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But where classes come in all this picture.

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So let's go over the whole hierarchy of all entities and see who is the parent of who.

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It's very, very simple.

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All right.

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So first of all, here in the bottom left, we have in the screenshot we have a file called Filed by.

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OK, so the file of Python called a module.

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This is the official name of a file entity.

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It's called a module.

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OK, and then beneath it, OK, beneath it.

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Meaning in the hierarchy, inside inside this file, you can see here at the top as the first hierarchy

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inside a module is a class.

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OK, you can see here the class keyword colored in orange and then you can see this is my class.

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OK, this is the name of the class.

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And then to come afterwards, we will also discuss naming conventions between classes.

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You can see it's not written with small letters and the scores.

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All right.

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We'll talk about it in a few minutes.

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But the fact that I want you to notice here that class is the top hierarchy.

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Then you have some indention and you have a method.

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OK, and then you have some more indention and you have this.

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This is my variable equals five.

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OK, so class either is the parent of a method and method is the parent of a variable.

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This is how it works.

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Right.

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And just have a quick reminder regarding coding conventions.

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We always discuss that.

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I want you to become a professional developers and not rookies.

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And for that, each professional developer which will look at your code, you'd notice if you a pro

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or not, simply by the naming of your entities inside your code.

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So I have to mention that classes goes with capital letters in all of the words and without underscores

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between the words.

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So you can see an example.

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This is my class right here.

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So this is the coding in the naming coding convention for Python classes.

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This is the official way to call classes.

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OK, so concluding the whole this whole session, we have a file which called a module, and then you

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have a class that is the top hierarchy inside a module and beneath it you have the method and then you

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have a variable.

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All right.

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Let's go further down the road.

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OK, so now we already seen here a creation of class, by the way.

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You even you haven't even noticed.

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OK, but now let's see how to create a class.

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What are the rules?

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What are the simple basic rules?

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OK, so let's look at this part.

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OK, so you create a class, use the keyword class.

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Obviously, we just talked about it.

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And let's see, how can we do classes declaration.

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OK.

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So once you want to declare a class, just write the class keyword and then write the name of your class

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with capital letters with no underscores between the letters and then put to dots afterwards.

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OK, so this is classic Liberacion.

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Then in this specific example you can see a variable is stored straight away under a class without any

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method inside this class at all.

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OK, and this is not a problem because here you can see the class is there like Grant.

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OK, you have two generations here.

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Class is the grandparent of these variable meaning class is on top of variable.

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So once we are not having this method here, it's OK.

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So a variable can be stored.

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Class is this is not a problem.

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OK, and you have a simple variable here, you equals two thousand.

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This is a simple variable and set a class and that we have just a simple PERENT action, by the way.

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It's an error because it's not an ear, actually, it's a car owner.

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Just fix it like that.

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All right.

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So we have here a class declaration, we have a class name, we have a variable and we have a simple

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print of that variable.

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All right, so there you go.

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We have created a simple class, not very difficult, nothing to worry about, you see, just declaration

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and then you can put stuff inside it for now.

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All right.

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So now we can use the class of car class, this class, and let's create an instance of an object or

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an instance of a class also.

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All right.

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So we have this class and we want to create an instance for it.

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So this is like the old car sketch from the previous lecture where we've seen, like, a simple old

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geraud car.

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OK, so this is it.

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And now we want to create an instances out of it.

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OK, so this is how you do it.

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All right.

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So here is the class declaration, as we have seen a few few moments ago, right here below, you can

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see an instance of an object.

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OK, so at the left part, just right the name of your instance, you can give it any name, same as

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a variable.

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Just give any name, small letters with underscores.

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OK, it's a variable.

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Then you put equals and then you put the name of the class that this instance belongs to.

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OK, the Audi underscore a three instance belongs to this car class.

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So just write the name of the class.

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OK, so we have now an Audi A3, which is an instance of car class, and we also have a Ford Focus,

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which is a second instance of an object or instance of a class.

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And it also equals two cars class meaning.

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Meaning you can imagine that you have an arrow, an arrow going from Ford Focus, going to car class,

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then going on top and going inside car class.

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OK, and also from all the three Audi A3 goes an arrow to car class and then goes straight inside car

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class.

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OK, so both both of these instances belong to car class and therefore they're called an instance of

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an object or an instance of a class.

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OK, there are several names for these instances.

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All right.

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This entity called an instance, you have several names for them, for it.

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And they're basically mean, the same instance of an object object instance or instance.

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You can find all of these names and stack overflow or in articles that you read on line.

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So each developer calls them differently, but it means the same thing.

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So this is basically what we have here, a declaration, which is the top part.

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And we have two instances of an object.

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OK, this is the first instance, Audi A3, this is this is the second instance, Ford Focus.

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And they're both belong to the car class.

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They're both instances of the car class.

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Um, I think this concludes the first part of classes.

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Let's discuss some more of these topics in the next lecture.

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I actually think that in the next lecture we will discuss what our properties of an object and what

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is a self parameter and also how to use object methods.

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All right.

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I think this is it for today.

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And I will see you in the next lecture.

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Thank you.