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‫Narrator: Hi.

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‫Inside of this lecture we're going

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‫to learn something called array list.

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‫Working with arrays is cool actually.

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‫Okay, I'm going to name these arrays

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‫and how even cooler data structure called

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‫the array lists.

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‫So sometimes you see as lists

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‫in other programming languages.

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‫In Java, we call them array lists

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‫but they're basically the same.

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‫It's actually the same thing with arrays

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‫but it's much more flexible

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‫when we compare it to the arrays,

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‫because over here when you initialize

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‫a new empty array

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‫you have to specify some kind of perimeter

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‫that limits the capacity of those arrays.

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‫But inside of an array list,

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‫you don't have to do that at all.

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‫You can just initialize an array list

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‫as an empty list and you can add

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‫or just remove any element

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‫that you may want later on.

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‫For example, you can just write array list

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‫and beware, there is some kind of

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‫angler parenthesis over here

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‫which is smaller or bigger size,

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‫and over here you have to specify the type

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‫of the variable that you're going to be storing

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‫and those array lists.

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‫So I'm going to call string for example,

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‫because they will be a string.

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‫It's going to be a string array list.

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‫I'm going to call this my musicians,

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‫okay?

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‫And I can come over here and just say

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‫this is going to be a new array list

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‫and close the semicolon.

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‫So maybe you can come up

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‫with situations like that

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‫where you will see the type

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‫in the second right side of the equation as well.

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‫Like new array list string over here.

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‫You don't have to do that actually, it's deductible

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‫but if you see it like this,

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‫yeah, it's okay as well.

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‫Okay.

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‫You have to be

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‫using this before

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‫but right now it's perfectly okay.

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‫So my musicians dot add,

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‫will add a new element to the array list.

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‫So it'll expect string,

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‫obviously, because we made it to be.

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‫Now I can just say out that print line

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‫my musicians dot get.

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‫And when you say dot get,

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‫it will ask you for an integer

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‫which is an index.

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‫Okay? So,

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‫I'm going to say zero because we are already

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‫have only one over here.

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‫It will bring out to James to me like this.

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‫So I can add as many as I want.

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‫Like I said,

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‫I can say my musicians dot add Lars,

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‫and I can come over here and say my musicians dot add

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‫and actually I can add it anywhere I want as well.

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‫It has some different values, different properties

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‫different methods like this.

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‫As you can see,

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‫you can just specify the string

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‫but you can specify the index

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‫if you want as well.

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‫For example, you can say that,

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‫yeah, add large but add it to this index.

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‫Okay? I don't want it to be added

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‫on the last index that you're available.

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‫I want Kirk on the first index

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‫which is the second element of this array list.

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‫So it will be James, Kirk and Lars

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‫in this case, right?

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‫So let me do it like this.

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‫I'm going to add another one called Rob and

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‫let me just

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‫get everything in this list

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‫so that you can see what's going on,

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‫rather than zero,

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‫I'm gonna say one, two, and three.

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‫And later on, don't worry.

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‫We are going to see a perfect way

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‫to get every element inside of an array list

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‫with a single method.

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‫So here you go, James, Kirk, Lars, and Rob.

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‫If we hadn't had this index thing

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‫then we would have seen James, Lars, Kirk, and Rob,

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‫but this time we see James, Kirk, Lars, and Rob

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‫because we specified Kirk

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‫to be put into the first index

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‫as the second element inside of this array list.

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‫So that's how you work with array lists.

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‫As you can see it,

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‫it's much more flexible when we compare them to the arrays.

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‫You can just not specify any kind of capacity at all.

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‫You can put the elements

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‫in whatever index you want

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‫and it's perfect for working with data

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‫that you are not sure of.

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‫Maybe you're downloading it from internet

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‫and you don't know whether it's going to be ten elements

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‫or 12 elements or 1000 elements.

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‫So you're gonna come across array list

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‫in the Android applications very often.