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Welcome back.

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And this week, we are going to look at aerialists and we're going to use the radius quite a bit in

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

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So they are used to create dynamic arrays and arrays are types of collections.

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So we are going to use collections here.

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So why should you use an array lists?

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Well, realists 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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Their latest class provides both read and bright functionality.

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Then the list follows the sequence of insertion order.

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So it matters when you put something in there and an rest is not synchronized and it may contain duplicate

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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 apparatus.

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So that's the basic constructor.

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Then you have another constructor where you can actually pass in the capacity.

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So you can say what the maximum amount of elements that can fit into this are rightest should be.

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And then you can create and the rate is based on a collection.

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So you can fill it with the elements of a collection and use it then as you need it.

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Examples of functions.

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Authorities are, for example, the ADD function used to add the specific element into the collection.

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Then the clear function is used to remove all elements from a collection to get function allows you

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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 four 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 and hereby say a single instance.

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So let's say you have the value five multiple times in there.

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

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Then there are, of course, many more functions in their Raila's 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 O'Reilley so you can see we create an array list and we created

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via the virtual keyword.

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So we're not using var here because even though the array list might be a also an immutable array list,

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it's still adjustable.

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So we cannot replace the array list object, but we can replace the content of this relist object.

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

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For example, the array list, add one and then add two.

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So I'm adding one and two to this list, meaning the written words, and then we can print this array

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list by using the four in loop here.

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So for Mineralised we print I and that will output one and two the register 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.

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This time we said there's a list as being limited to five entries.

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So this is the one example where you can limit and the rate is to add a certain amount of values.

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So here this one.

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And then we have a list which is a mutable list of strings and we put values in there and then we add

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all of those values to our greatest.

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Then we use an array list iterator called ETR in our case, and we say as long as this iterator has

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

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So we're just printing it out next.

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

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means in the list itself.

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

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So that will give us the following output.

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One, two.

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And then of course, the size of a list is two because there are only two entries in there.

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

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let's look at the jet function.

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You can see again, we have a main function here using an array list of strings and then we add one

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and two and then we loop through it with this 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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What we're doing here is we are accessing index one, which means we get the two and that's why the

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output is to in this case.

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All right, this was just a little introduction to aerialists, we are going to use them quite a bit

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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 contacts 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.