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Hi guys.

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Welcome back to another class of our course about them.

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So in this class it's very simple.

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My goal is to talk to you guys about another way that you can store your data as well as convert your

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data from one that I type.

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Well from one type of data to another type of data.

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So not only converting numbers into let's say certain strings but also converting certain strings to

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another types of strings.

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So it sounds maybe complicated but you'll see it's very very easy.

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So basically what we are going to talk about are dictionaries in Python.

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So what's what exactly is a dictionary in the normal world.

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So when let's say a real dictionary is basically a place where you can find out a word and the definition

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of words of this word.

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So it's gonna be one word linked with many words in Python.

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It's the same thing.

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So you guys will take one word.

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So it could be a string or a set of words and make it equal to let's say another set of words.

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So this is a way that you guys can store your data and also converter that as well.

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For example if you want to make a list of employees.

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So for example we can have no the number of each employee and you can have the name of the employee

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associated with his number.

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So in this case yes.

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As you can see this is a way that you can use dictionaries.

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So Michael today is really to present you this useful thing that you can use in Python and give you

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two examples of how you can use.

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Well this dictionary and those two examples well they can apply yet in everyday life.

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All right.

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So let's start first thing before.

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Well first thing that you guys can understand I have to understand is that dictionaries can store any

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type of data so it can be.

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It could be strings it could be numbers and they can convert.

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Well you can store a string with a number or a number with a string.

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You'll see it's a very very simple to use.

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All right.

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So let's begin.

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So how do you write down the dictionary.

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Well it's very simple.

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It's like writing down a variable.

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So it starts the same way.

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So let's say our dictionary will be named colors in this case will have our first example would be colors.

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Then you click on equal.

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Instead of writing down a sentence like you would do for a four when you are creating a variable you'll

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simply open up this parenthesis.

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So in this case those parentheses are used for dictionary.

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So everything that is inside of those parentheses will be all the words that we'll have for our let's

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say our dictionary.

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All right.

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So the first word that we are going to use as our dictionary will be blue.

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So we will generate Blue by simply the first letter of this word.

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So let's say B in this case will be equal to blue.

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So be two points in this case write it down like this.

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So B two points is equal to blue.

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So very important.

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This is your first word.

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So in this case this will be the key.

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And this is the same word.

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This is the word that is linked with the key.

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So you write down your word you're your first word the key right here and the second word will just

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be linked to it.

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So when you are going to make a search for inside your dictionary you're going to make a search for

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the word that is right here.

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And this is going to be your output.

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All right.

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So this is your first word.

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Let's say we want to add more more words in our dictionary.

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So very simple.

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You click on the comma and you add your second word.

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So in this case let's say want to do the same thing for red so write down are two points Red

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let's say wanted the same thing for orange.

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So.

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Oh we write down two points and we write orange.

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All right.

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So let's just Kip do those two words inside our dictionary.

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So as you can see each letter will refer to a word.

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So very simple we stored this inside of our dictionary.

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So another thing that you guys need to remember you can't have two letters that are the same so two

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keys that are the same.

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So in this case I can't have it be used two times.

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So let's say for example I tried let's say on a store before.

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I don't know.

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B for ball.

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So I want to add a ball.

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So as you can see it's not going to work because B is written two times here.

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And if you store the same let's say a word two times it's not going to work.

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So here for example it's B.

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So if I have two same values to same two keys that are the same.

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It's not gonna work.

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So you need to have two different keys.

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Great.

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So right now we have those three words and let's say our goal we want to fight what we want to look

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for.

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The word are.

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So imagine you have millions of words and you want to look for are right here.

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So how exactly would you look for.

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So the first thing that you guys will do is write down what print.

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Because we want him to be printed so they don't print we write them or a dictionary name which in this

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case is colors

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dot jet.

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So in this case does get here will have two values.

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So the first value will be the value that we are looking for.

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So in this case we are looking for B

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or r or any value that you want to look for.

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So let's say we are looking for a B.

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And the second value will be the default value so in this case let's say it's going to be stopped.

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So the default value is simply the value let's say.

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If for example the diction Python doesn't find the word in the dictionary he will return the default

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value.

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So for example let's say instead of b we have I don't know h and we don't have each and our dictionary.

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So python will return stop.

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So let's run the app and see what it looks like.

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So as you can see B stands for blue.

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So it returns blue.

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If for example instead of B will write down 0 which is orange we run our app as you can see it's going

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to give us orange.

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But let's say we write 0 with a capital letter.

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We don't have it in the dictionary.

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So as you can see it's going to generate stop because we don't have this value.

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And if we can generate let's say write down I don't know G for example we don't have it.

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So it's going to generate the same stuff.

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So the full value simply the value that is generated when the value of the word where the key doesn't

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exist in the dictionary.

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All right.

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So the second example that you get that we are going to do today is very simple.

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We will create employee numbers and we are going to look for those employees.

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So let's let's creates this basic app so let's have I don't know five numbers.

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In this case we'll have five numbers and give random names.

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So let's say.

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Name a.

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So a random number and a random name.

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So in this case the name B

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and let's say named C..

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So my goal here is to present you that you can use dictionaries for names for names for strings as well

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as four numbers.

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So in this case we are going to use a dictionary for numbers and we'll find out numbers.

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Well we'll find out names by using numbers

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grip so let's do it.

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As I explained the here it's going to be names so I explain the formula to write this down the function

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to write this down is very simple.

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Simply write down names so your dictionary named dot get footnote up your parentheses.

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The first thing that you guys will write down will be your value your key sorry.

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So in this case it's gonna be let's say we are looking for a 150 to and the second thing since it's

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a number we keep it like this.

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And the second thing is the default value and in this case the default value will be let's say uh this

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name doesn't exist don't exist.

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All right and want to print all this

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here.

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All right so simply run the app and as you can see the number one hundred fifty two is then the A.

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If we change a number and write down some five for in this case it's gonna be the name D but let's say

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we write down 9 9 9 by some during us this name don't exist.

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Let's see.

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This is the definition of a dictionary in Python.

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You can see what is it exactly right now.

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And right now I think you can work with this.

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Well this thing that is a dictionary so that's it for this class guys and see in our next class.