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Hello.

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Welcome back.

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In this lesson we should take a look at classes and object and this is a very quick introduction to

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object orientation in Python.

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So objects you can think of objects as an encapsulation of variables and functions into a single entity

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so objects are like verb and functions proved to get and combined into a single entity an object to

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get the variables and functions from classes.

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Classes are essentially templates to create our object.

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So let's see how to do this.

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I'll close this and create a new project over here for file new and then I'll press control as to save

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and then I'll say this is number seven on the school I call this classes and to create a simple class

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we can close this one here to create a simple class we can just use the class keyword class and then

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the name of the class.

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This is simple class and then we put some cool on here we hit enter and then we can give the class a

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simple variable.

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This rebel the class contains a variable called Hello.

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And we can assign a value to hello hello.

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The class contains a simple variable known as greeting and we can assign hello to greeting.

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So the class contains this variable.

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Also we can add a function to the class so we can hit enter.

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Come down here an added function and we can say.

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Def function 1 and then into brackets here we put self and then we hit enter and then now we can write

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what we want this function to do.

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We can say the function we want the function to print

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this is a simple class like this.

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So this is it.

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This this is a very simple class.

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So now how do we use this class.

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We can create objects from this class.

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So we can we can come down here.

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Let's test it.

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So to test the class we come out of the class just like we came out of the function earlier so we can

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create a simple we create a variable here on a simple object and simple object.

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Here we can assign our class Singapore class right like this.

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So let's run this and see what we get.

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So first of for this entire section is not to make an expert in Python.

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Like I said we just getting used to some of the concepts and basics and then we go straight to DSP.

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All of this.

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There is much more to it.

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This an entire book can be written on Python object orientation but this is just to get you familiar.

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You don't need all of that.

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I'm giving you just the foundation you need to do your DSP and you've been machine learning stuff so

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you will click over here to run the module and save.

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Okay and then over here simple object we have this as an object of the class so to access the class

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members or to access the content of the class.

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Just a simple on the school object

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we could assign let's say we want X X because Mexico's simple on this call object

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that variable or dot region creating this court or greeting is the verb with the right word is called

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greeting.

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As you can see as I said simple object dot the ideal is helping me with what the class contains.

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So I could either choose the function or degree tense so I just say greeting her and then I'll hit enter.

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So if I say X to print x I get hello in the same way.

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We can just we can see why.

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Because simple on the score object.

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This time we can just see the function and a few and see the function is.

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If u n c t front 1 and then we hit enter and then this time we don't need to make it print because the

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function automatically print.

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The reason why we had to say X us in print x is because this hasn't got a print statement but a function

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automatically print this and we can create as many objects as we want actually.

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So this is just simple objects.

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We can say simple on the score object to call a simple class and we've just created another object and

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we can see a simple score object to

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front one and it's going to print the same thing.

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So this is a very very simple class.

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We've demonstrated here.

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It doesn't do much to just print stuff but you get the idea.

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So let's see on that example this one with much more content so let's say would create another class

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called computer.

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I'm going to come down here and see a class computer and I'll post some cool on here and I can create

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the first variable of the class.

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Let's call it name.

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And this is going to be left empty like this and then hit enter.

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We'll create another variable called kind and we can give this this variable a default value which is

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laptop.

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How about that.

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And then we come down here we say color and we'll leave it empty as well and we'll come down here and

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we give it a cost.

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Let's see another variable cost space this out to improve readability a bit you can give it a cost and

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let's give it a default course value of five hundred and we can add a function.

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So we've got four variables in our class.

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We can at least one function just to make it more fun so we can see the F this is how we create functions

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and can give the function a name.

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We call this description like this.

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We can pass self here.

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You can put up some call on here and what we want to do is we want to create a string once grade this

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string and this string.

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We wanted to say percentages is a percentage as percentages with percentage to F.

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And basically what we're going to do is we're going to say laptop we're going to let us going to let

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a user assigned a name of the computer.

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So if you put Doe here it's going to say Dell s if you put color red.

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So Dell is red.

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And then if you put kind laptop or that desktop it's going to be Dell is a red desktop with cost basically.

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So this is it.

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And this a creative way of putting it all together.

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Percentage is is a percentage as percentage as with percentage points to.

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And this is this one is useful float.

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They pointed to efforts with two decimal places.

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So then we come over here just like we did earlier when we're seeing the functions we come over here

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and we put a percentage here and then we put all the variables we want to assign and we've got a self-taught

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name self the color self kind self or cost.

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So these are then these variables here where we assign them we come here and then to be added to the

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string automatically.

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Very simple.

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And once that is done we can return the string so we can see return to s desk SDR here description string

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and then we can see control.

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So let's go to the let's run and test it out with the other window right ID and just put the test code

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here.

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So click over here and then click on module and let's see.

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We want to create a computer class so we can see a computer one because computer like this.

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So we've created the object let's say we want to create a computer object it's as simple as computer

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one of course computer.

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So no no we've created the object the objects known as Computer.

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Let's give our computer a name of say computer computer one object a school computer one dot then we

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can pass name and let's say we assign something like Dell Latitude it's one of the popular computers

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grew up using put Dell Latitude once that's done we've given our computer objects known as Computer

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one to name.

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How about we give it a color so I can come here and see a computer one dot collar like this and we can

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say block like this.

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Once that is done we can give it a cost and a kind word denote a kind.

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So this that then we've not given the kind yet.

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So by default our class says kindness laptop.

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If we've not given a kind that default is going to be used if we do not give it cost the default cost

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is going to be use.

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But let's change the cost here just to you know add some variation.

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So I say computer 1 that cost because 800 like this once they stand we can say print computer one dot

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description so we access and they function within the within the class computer 1.0 description and

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we don't have to pass any argument cost indicated we already passed the argument that supposed to be

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printed we hit enter.

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And he says Dell Latitude is a black laptop with five hundred dollars.

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What happened.

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OK.

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So we did an assigned cost.

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We have a typo here instead of cost.

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It's written.

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Oh yes.

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That's why it's using the default cost so less assigned cost.

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Say computer one does cost u s t a course.

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Eight hundred 800 hit enter and no less print print into bracket computer one dot description like this

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will hit enter.

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OK so we have an error here.

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Very very simple error.

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Just bear with me.

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We passed cost as a screen care.

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A mistake cost everything else is a string.

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So it's easy to get confused though it's easy to forget.

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Cost is not a string.

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So we don't need this quotation marks around cost so we can come here and see a computer one that cost

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because he 200 like this will hit enter and there.

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Now we can print Computer 1 dot description

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like this and we'll hit until like this and it says Dell Latitude as a black laptop with eight hundred

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dollars.

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So this is a very simple very straightforward.

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This is how to make use of classes.

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Yeah.

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We just have one object.

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We can make 10 object and we do need to create all of them from scratch.

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We can have another.

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We can create a new computer computer 2 equals MacBook.

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Computer to color.

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Course wide computer to prize of course 2000.

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And we have it do the same thing MacBook as a white laptop worth two thousand dollars.

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Yes.

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So this is a very simple example for how classes are used and how they behave.

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This order is for this lesson.

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If you have any questions at all send me a message or leave it in the questions area.

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Have a great day.

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By.