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Cheers and welcome back to another class of our course about the complete introduction to Python.

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So in this class we are gonna talk about a very important thing which are strings and we are gonna talk

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about different manipulations that you guys can do with the well with strings.

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So as we talked in our last class strings are simply text that you want when if you want to add text

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to your code to when you are programming.

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Strings are simply a way that you can add the text on your let's say on your code when you are programming

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something.

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And this is why it is very important to understand how we can work with them what exactly we can do

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with them and what are the different manipulations that we can do with them.

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So in this course how are divided all this.

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We are gonna talk about the first thing storing data in our variables.

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So storing strings in our variables we are gonna talk about the string storage after that.

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Well will talk about the storage and how we can manipulate it after what we are going to talk about

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functions.

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So what is some different functions.

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There are hundreds of functions that exist for strings but we are going to talk about the most common

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ones.

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So in this case if I'm not mistaken we have four of them.

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And finally we are gonna talk about a small little thing that you guys can do.

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Once again you'll see this by the end of this class.

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So my goal right now is simply to present you what you can do with strings.

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Once again it's going to be some basic manipulations but you guys will see it's gonna be really cool.

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So let's start.

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So the first thing I'll ask you guys to do is simply open up your by charm or your.

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Any text editor that you guys use to be able to run Python when it's all done.

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The first thing we will write down is simply a small sentence or in this case will write down print.

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Let's say I love pizza.

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So we will print.

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I love pizza

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in our goal right now.

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Simple simply just run it so you can see we have our way hour our string which is I love pizza and we

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have our small app that is printed right here so our app we asked Python to print.

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I love pizza but well you can also do we you can store this instead of printing.

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I love pizza.

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We can store this string into a variable so let's say for example we want to create a variable that

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we will name sentence and we want to store it in it.

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I love pizza so we store.

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I love pizza all right.

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And we can run it so we can see we have I love pizza first.

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So just create our second function so in this case we want to run.

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All right.

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So as you can see in the first case scenario we print I love pizza and we run.

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I love pizza so the app is simply asking Python to run this text the second so in the second thing right

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here.

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So if we run it in both cases it's reading.

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I love pizza.

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But in the second part right here what we ask Python to do is add first name sentence.

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I love pizza so we going to store in the variable sentence the data.

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I love pizza and then we ask Python to run this variable which refers to I love pizza.

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So you get the difference.

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So instead of writing down the whole thing each and every time we can simply store it into a variable

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and ask Python to run it right after that.

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All right.

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So we'll just delete the first part of the code when it's all done.

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The next thing that we will talk about so right now you understand the data storage.

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So even if we change the I love pizza instead we write down.

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I love pizza and let's say nachos and we run our code.

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You can see that python will still print our sentence which is I love pizza and nachos.

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All right.

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So I know that you guys understand the first part which is storing data into a variable.

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Well storing a string into a variable we're going to talk about the second part which is in this case

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functions so functions are a very important part in string manipulation and we are going to talk about

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some basic functions that we are going to use for discourse.

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So you'll see it's not that hard to understand.

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You can do some cool stuff with it.

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Right so the first thing that we will talk about will be our first function which will be the upper

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function.

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So in this case what we want to do is simply take all the characters of this will of this sentence which

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is I love the work of the string and we want to put them all into upper characters.

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So how we'll do this.

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It's very simple.

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We'll write we have right here our Well what we ask.

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Bite onto the print and we'll ask him to print sentence.

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So at the end of sentence simply click on that and we'll write down our function.

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As I said our function is the upper function.

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So you just write down upper you open and close parentheses.

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And when you run the app as you can see Python printed I love pizza and nachos in upper cases because

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we asked Python to print our our app in upper cases.

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All right.

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So when it's done the next thing that I'll ask you guys to do in Sim is simply take some letters in

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a while in complete randomness and put them in the upper characters

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when it's all done right now what we'll see we'll see that python.

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There is also a way for us to ask Python to put all this sentence in lower characters.

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In this case how this will work.

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It's simply another function that we'll use.

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So how do we read this function.

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We will write it down the exact same way.

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So let's start from the beginning.

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We have our print sentence.

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So this is the code that will ask Python to execute.

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We have our sentence we'll write down dot and then our second function will be lower so lower and you

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open and close parentheses.

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And then the next thing that you guys will do is simply run the app so you can see I love pizza and

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nachos is on in Lower cheese.

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All right.

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Amazing so right now you know how to put all the characters in your in your python string in upper or

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lower case Larry.

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Now let's say that you guys want to verify if all characters are in lower character so you can ask.

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There is a way that you can ask Python to verify this so you can ask python is all the characters right

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here are in low are lower chapters.

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So how we will do this instead of writing lower we simply will write down is lower.

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So this is showing up.

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So you simply write don't print the sentence.

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Dot is lower.

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So right now you ask Python if all those characters are in lower character.

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So we'll run the up.

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And as you can see Python returns us false which means that all the characters are not in lower chases.

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All right.

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But right now let's verify it.

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If we put all the characters in lowercase is sold.

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This is very simple.

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We'll call it.

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We'll have our right here print.

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So let's do it step by step.

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So we have our first part of the code which is print sentence.

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We ask Python to print this part of the code.

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So the first thing we'll do we'll put everything that is here in lower case is how we'll do this.

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Simply write down sentence dot lower.

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So the first part is putting everything in lower cases.

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So we have our first part of the the app.

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The second part will be asking Python if all those if all the text in this string in this variable is

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in lowercase i will do this.

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We'll simply ask him is lower and we open in close parenthesis.

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So when it's all done we run our app.

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And as you all right.

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Don't forget to add the double parenthesis they both please.

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When it's all done you can simply run your app and as you can see it returns the value.

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True.

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So very simple what you what is it what exactly happened here.

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You printed sentence then you asked Python to put everything that is in this variable in lower cases

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and then you ask python is everything in lower cases in this in this variable.

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Right.

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So this is the first the thing that we will that we saw today so right now you know how to put everything

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in lower or protractor and verify it.

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So as you can see it's very simple to do than say well the another function that we are going to talk

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about is a function to calculate the length of a certain let's say string.

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So in this case this is simply another function.

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It's very simple to use.

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So what we'll do we'll write down once again our first part of the code which is print sentence we ask

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byte on to print the variable sentence.

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So we'll just try if it works.

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Yes it's the works.

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Amazing.

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So right now what we'll do we'll work with our second segment function.

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So it's the function length.

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So how do we write it down.

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Very simple print.

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Then you write down L E N and you open up your parentage and close it.

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So let me explain.

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Let me explain to you what exactly happens here.

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So you ask Python to print.

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So you ask Python to print you right here the length of this variable so you get it first part of the

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code asking Python to return you the length of this variable in this case the length of this variable

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is twenty three because we have twenty three characters and I love pizza and naturals.

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Let's say we write down and I don't know.

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And tackles.

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So we run our code and right now we have 33 characters in our sentence.

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So you get the point.

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All right.

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Next thing that we want to do right now you know how to calculate the length.

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So very simple you print.

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I'll repeat it once again.

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So you print the length of this variable very simple to understand it even if you change the length.

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Well python will adapt and change the answer that it will give you all right.

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The next the next vote the next function that we are going to talk about sorry will be the function

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of replays.

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Let's say you want to replace a certain variable right here by something else.

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So in this case I will do this.

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It's very simple.

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So we have our first part of the code which is the string.

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So you simply write down print you open up your parenthesis and you write down a sentence which is your

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stream.

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All right.

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As I said the next the next function will be the replaced functions or simply click on dot replace and

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you open up your parentheses.

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All right.

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So the first thing we'll ask will have to do is write down the word that we want to replace.

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So in this case the word we want to replace will be pizza.

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Let's say it's pizza.

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So you open up your will to commas and you write down pizza.

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So very important you need to write down the same letters that are here.

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You can't use capital letters when it's not capital letters.

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When you choose choose the word simply click on comma and write down the word which by which you want

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to replace me.

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So it's a want to replace pizza by hamburgers

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and simply click on play.

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So as you can see right now our app will return this.

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I love hamburgers and nachos and tackles.

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Since we have our variable right here and we ask Python to print all this.

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So very simple to use as well.

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Let me explain to you one more time.

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So you ask Python to print this variable in which you will replace the word pizza by the word hamburger.

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So as you can see it's simply you are you simply talking with the computer.

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So you ask him to replace things.

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So it's very very simple to use another variable that we owe another viable so another function that

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we will talk about.

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Once again it's a very simple function to use is the index function.

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In this case if let's say we are looking for a certain character it will give us the number of the character.

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So let me just show you this real quick.

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So how will write this down.

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Very simple.

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We'll write down our first part of the function which is well the function will write down a first part

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of the code which is print sentence.

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Then we click on index.

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So the index function and let's say we are looking for the letter B.

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So in this case we're looking for the letter P and we play Oracle

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here we go.

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So as you can see it's going to be the seventh.

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It's the seventh character.

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Yes it's maybe not the seventh but when you calculate with python you start to calculate with the by

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year the values you saw in this case we have zero one two three four five six and seven.

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And yes you have to calculate the spaces also so you don't start to calculate by would 1 you start to

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calculate with 0.

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So this is the main difference between python and let's say when you calculate by yourself Python Keller

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starts by you so the eye right here will be zero.

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The space will be one the L two three four five six and the feet will be seven.

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So let's say we will.

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We are looking for the A.

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In this case the first a and we run our up.

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It's gonna be the eleventh charity.

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So if we are looking for something Python can simply well find that out.

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Let's go.

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Also is that we can look for complete words.

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Let's say we are looking for this.

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And so we just write down our weird end which is a and in the letters in the in small letters and python

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will return the value thirteen which is the value of the well will return to start the beginning of

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our let's say in this case of our end which starts at the value thirteen.

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All right.

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So after all this you can simply well you can simply delete all this.

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So another cool thing that I wanted to show you guys it's going to be the last thing that I'll show

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you is let's say for example you have a sentence and you want to print.

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Well you want to print a part of the sentence at.

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On the first line and then add the second line.

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So let's write down print and let's write down something.

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Well once again I love pizza and nachos and backwoods.

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All right.

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Perfect.

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So right now if we want to drop what.

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Well if we run all this we have our sentence which is I love pizza and nachos and tacos.

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All right let's say we want to drop the first the first part of our sentence.

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We want to drop it here.

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And the second part lower even lower.

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So we'll do this is very simple.

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You simply have to draw this line and write it in.

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So when you run your code you will have.

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I love pizza and nachos.

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So let me just read it once again.

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As you can see and let's say we want to do the exact same thing in this part of our code.

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We can do with simply like this.

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So if we run the code as you can see it's right now running on three different lines.

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So each time that you each time that you want to ask Python to run a part of your code on another line.

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It's very simple.

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You simply have to put this symbol right here and the letter.

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And so it will simply run your code on a little red line.

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Right.

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Right now you understand how you can manipulate strings.

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And while some basic string manipulations we talked about some functions right now we talked about storing

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variables.

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Well we've talked about storing string in variables and how we can use it.

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So until now you can just practice it and play with it you'll see it's very cool to use.

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There are as I explained there are hundreds of other functions that you can find on the Internet with

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strings if you guys are interested.

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I and I what I definitely suggest you to go on Google and look for those functions and you can play

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with them.

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Also they're not very hard to understand and normally they use it's easy to use.

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So that's it for this class guys.

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And see in our next class.