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Welcome back.

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And this video, we're going to look at ArrayList and we're going to use the rails quite a bit in our

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future project, so it's important to see how they are used and understand them so they're used to create

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dynamic arrays and arrays are types of collections.

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So we're going to use collections here.

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So why should you use an array lists?

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Well, relics are used to create a dynamic array, which means the size of an array list can be increased

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or decreased according to your requirements.

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So it's not limited to a specific size, which is pretty cool.

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The ArrayList class provides both read and write functionality.

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Then the ArrayList follows the sequence of insertion order, so it matters when you put something in

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there and then the radius is non synchronized and it may contain duplicate elements.

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So it's not going to be limited to one entry of the same thing, so to speak.

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The constructor of an array list looks like this.

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So either this used to create an empty ArrayList, so that's the basic constructor.

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Then you have another constructor where you can actually pass in the capacity so you can see what the

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maximum amount of elements that can fit into this array test should be.

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And then you can create and the rate is based on a collection so you can fill it with the elements of

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a collection and use it then as you need it.

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Examples of functions of a rapist are, for example, the add function used to add the specific element

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into the collection.

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Then the clear function is used to remove all elements from a collection.

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To get function allows you to get an element as the specified index.

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So, for example, if you want to have the fifth entry, you could enter index for in there and you

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would get that.

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And then the remove function is used to remove a single instance of the specific element from the current

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collection if it's available.

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And hereby I say a single instance, so let's say you have to value five multiple times in there.

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Only the first five would be removed if you call this remove function with the value of five.

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Then there are, of course, many more functions in the ArrayList class, and we're going to use multiple

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of them, but these are the most important ones.

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All right, let's have a look at an actual ArrayList so you can see we create an array list and we created

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via the valid keyword.

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So we're not using VAR here because even though the ArrayList might be a vowel, so an immutable ArrayList,

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it's still adjustable.

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So we cannot replace the ArrayList object, but we can replace the content of this ArrayList object.

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In this case, it's in ArrayList object of type string, so we only can add strings in there.

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For example, the ArrayList add one and then ArrayList add two.

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So I'm adding one and two to this ArrayList, meaning the written words.

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And then we can print this ArrayList by using the for in loop here.

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So for I in ArrayList, we print I and that will output one hand to the rest using collections.

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Let's have a look at that.

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We can see we have again the function main and then we create an array list this time.

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We set this list as being limited to five entries.

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So this is the one example where you can limit an array list to add a certain amount of values.

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So here this one, and then we have a list, which is a mutable list of strings and we put values in

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there and then we add all of those values to our ArrayList.

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Then we use an ArrayList iterator called Ittihad in our case, and we say as long as this iterator has

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something so as long as our ArrayList has another entry in there, we run to run this while loop.

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So we're just printing it our next.

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So the next entry in our ETR, which in this case means in the ArrayList iterator, which pretty much

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means in the ArrayList itself.

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And then we can also see that we can get the size of an ArrayList by using its size property.

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So that will give us the following output one two and then, of course, the size of a realist as to

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because there are only two entries in there.

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Now, let's look at the get function, so you can see we have this main function here again with.

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So then let's look at the get function you can see again, we have a main function here using an array

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list of strings and then we add one and two and then we loop through it with this for loop.

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But we also used to get function here in order to see what we will get.

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So if I use get one, I will get two.

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So this is a little confusing, but that has to do with the counting starting at zero.

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So the first entry here is going to be at index zero.

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The second entry will be at index one.

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And what we're doing here is we are accessing index one, which means we get the two, and that's why

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the output is two in this case.

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All right, this was just a little introduction to ArrayList.

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We are going to use them quite a bit and then they will become natural as usual.

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So no worries there.

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It's like learning a new word in a foreign language.

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The more context you see this word and the more it makes sense and the better of an understanding you

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get for this word.

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So see you in the next video.