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In this video we're going to focus on Javascript variables and their syntax.

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So variables are a concept that exists in every programming language out there.

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And the basic concept is always the same.

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A variable is a container that has a name on it and inside of that container we store some bit of data

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.

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So we saw the basic primitive types.

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Things like strings and numbers and booleans and variables are just a place a container a jar where

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we can put one of those in and give it a name that we refer to later.

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And then of course the name variable means that the data that we store in that jar in the container

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can change you can vary.

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So variables are really important.

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They let us store some data and recall it later.

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So we could have a variable called Current logged in user if we had a website with user log in and it

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would just know the user name of the person who was logged in.

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And it could vary and it would change.

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And then as soon as someone logs out it's then set to be empty or false or something we could have another

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variable for our tic tac toe game called Current turn and it would switch between player 1 and player

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to player 1 and Player 2 and that variable is in charge of knowing or keeping track of which player

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is supposed to be going at any given point.

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So the syntax for variables in javascript is very simple.

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It looks like this.

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The VAR keyword V-A are space a variable name.

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This is up to us whatever we want the name to be called the label for that container equal sign and

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then a value and then a semi-colon.

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We will talk a lot more about when you need semi colons.

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For now everything we do will be able to get away with a semi-colon or not having some a colon.

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When we talk about style and convention we'll talk about that.

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But for now put a semi-colon at the end.

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So here's three examples of variables.

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The first one far name.

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So I'm calling this container name and I'm setting it equal to the string Rusty the next one.

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I'm creating a variable called secret number and I'm setting it equal to the number 73 and the last

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one and making a variable is adorable and setting it equal to be true the boolean value.

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So let me show you how this works.

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I'm going to go ahead and open up my Consul here

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and I'm going to go ahead and make a first variable.

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So my variable will be called name and I'm going to set an equal to my wonderful dog Rusty's name and

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I'll hit enter and what I've done now is say javascript I need you to make some space and I need you

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to give that space a name called name.

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It's a little confusing instead of equal to resti.

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So now whenever I ask for a name I just type the word name.

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It's going to give me Rustie or whatever is stored in name.

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So the next thing is that I can change the value that's in there.

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So to do that I just reassign it.

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I just say name equal sign and I'll change it to be Tator that is terrible nickname I give him.

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And now if I ask for name again it's now Tator.

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So that's the important part of variables.

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They can change.

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They are variable.

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So in this example I'm recalling the value of name and then concatenating it with Hello there.

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So I'll just show you that.

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Let's make another variable this time called friend with our friends equals Sally.

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And then all I do is say friend let's do a hello there.

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Hello there.

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Plus friend and I made sure to add a space here so that when we add them together we have a nice space

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in our sentence and we get hello there Sally.

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And then if I change that and I now say friend is equal to no one.

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It's very sad.

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And I write the same line Hello there plus friend I now get hello there no one.

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So also just show to you we can store numbers in there as well.

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Can or any of the basic data types.

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So I'll make a number called Far numb equals.

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Let's go with forty three.

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And now whenever I refer to Nom I get 43 and I can do math with that so I can do something like no.

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Plus one hundred and I get 143 or I can do numb my mide two and I get one.

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Another important concept about variables and Javascript is that I can change their value but I can

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also change their type.

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So let's say that I want to change the value of knowm to the string 50.

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I can do that very easily like this numb equals.

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And I could either write that number 50 in there or the string the word version of 50 and it's OK that

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it's a string.

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It used to be a number before hand but I now change it to a string.

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Javascript doesn't care as a side note in some languages.

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That is a problem and you can't do that.

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Javascript has something called dynamic typing which means that it can change from one type to another

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without problem.

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So the last thing about variables that I want to touch on is that there's a convention for how we name

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them.

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And if you notice here they all follow camel case and that means that the first letter is always lowercase

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.

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And then if we have another word we uppercase the first letter of the new word.

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So camel case looks like this camel case and snake case which is another case you may hear uses underscores

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between words and there's one more often called Khabab case or Dasch case which is you use a dash between

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words.

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So javascript variables should be camel cased