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Hi welcome to Unit 11 which is all about javascript arrays so arrays are going to be our first data

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structure and data structures are just ways of storing data ways of holding information using javascript

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.

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So we've seen variables so far which will let us hold one piece of information like a name a phone number

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a number.

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But what if we wanted to have all of the names of all of our friends.

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Hopefully it's not just one but we have multiple friends and we want to be able to store all of them

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together.

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A variable is not really going to work for that.

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So the array is one of javascript's answers to that problem.

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So arrays are really really useful in all sorts of real world and practical situations.

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So a site like Facebook or Yelp they're going to have arrays all over the place any time that you imagine

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or you think of a list of data.

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So there's groups of data that are related.

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So let's take an example of it make a Facebook post and that Facebook post hopefully if it's a popular

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one let's say I'm getting married or I made a funny joke one time or someone close to me died and I

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get a bunch of sympathy comments.

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Whatever it is if I get a bunch of comments there's a list there.

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And Facebook stores them together it keeps track of them together using an array.

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We're going to use arrays to do things like keep track of that to do that you have in your To Do list

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or to keep track of the comments on a particular post or to keep track of the photos that correspond

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to a particular user.

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So they're really really useful.

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It's not just some construct something that you're learning early on but it's really something that

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we'll use throughout the rest of the course and I say that a lot and it's because everything I'm showing

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you is the stuff that you need for the rest of the course.

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So not just saying that a promise.

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OK let's get started with the race so we have three main objectives again.

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The first one is that I want you to be able to define race not explain what they are not that kind of

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define.

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But actually you use code to define an array and then remove and add elements from that array.

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The second objective is that you should be able to use builtin Array methods to add and remove and manipulate

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the array.

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So there are things like push and pop shift and an shift that we'll talk about.

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These are all built in methods that you should be able to use by the end of the unit.

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And then the last thing that we'll do is we'll build a simple project to do list application using a

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race.

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So will use functions we use arrays will these variables conditional logic.

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It's not going to be a fully functional crazy to do list with a visual interface just yet we will be

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working towards a really nice looking visual to do list.

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It's responsive and it looks really nice.

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For now this is going to be based in the javascript console.

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So I do want to set your expectations.

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We will be revisiting the To-Do list though and it will still use the race and functions and variables

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and everything else.

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All right so let's go ahead and get started.