So far we've seen how to create a list, add items to it and

access those items using their index.

We can add items to the list at the time it's created by using a collection

initializer.

We simply instantiate our list exactly as we had before.

Before typing the semi-colon we add opening and closing curly braces here.

We still need the ending semicolon though.

Now we can list the items we want our list to start out with just like we did with

arrays.

So I'll say Sue.

Bill.

Allen.

Beth.

And Mary.

Notice that even though we've only listed five items here,

the capacity of the list is eight.

This is because the collection initializer actually just calls the list add method.

This is exactly like creating the list and then calling the add method five times.

The list had two resize itself to a capacity of eight

when it got to the fifth item.

Again this is a good time to give the list an initial capacity and

avoid some overhead.

[BLANK AUDIO] So we can say five right here.

Another way to instantiate a list is with another collection

by passing it to the constructor.

So let's create another list called students2 and

we'll say new list string.

And we'll pass in the students list we created before.

Passing in another list essentially makes a copy of the list.

I could have passed in any collection type here, in fact,

passing in an array here is a good way to convert an array into a list.

We can convert a list to an array by calling two array.

So let's create a string array here.

Call it studentArray.

And set equal to students.Toarray.

We can iterate through all of the items in a list the same way we did with

the arrays.

We will use a foreach loop but we could use a for

loop for a while loop so say foreach string student in students.

And then we'll just print them to the console.

So I'll say console.writeline student.

We can also insert items anywhere in the list using the Insert method.

So I'll say students.Insert.

And here we specify the index that we want to insert the new item at so

I'll put something right it index 1.

And will insert Frank.

When we enter items into a list all of the items after where we inserted

the item get moved up.

So Bill, Allen, Beth, and Mary all had to be moved up.

This is not a quick task if there are a lot of items.

Also if there isn't enough room to add the item, then the list is resized.

There are a couple of ways to remove items from a list.

If we know the index of the item that we want to remove,

then we can use the remove at method.

Let's say Bill moved to another school so we need to remove him from the list.

If we happen to already know that Bill is at index 2,

we can say students.removeAt 2.

Now if we take a look at students, we can see that Bill is gone and

all of the items after where Bill was have been shifted back down in the list.

Like arrays, lists are not optimized to have items inserted into or

removed from the middle of them.

However, this usually isn't a big problem.

You'll find that inserting and deleting items from the middle of a list

is actually not as common in everyday programs as you might think.

There are collections that are designed to make adding and

removing items much faster though.

I'll mention some of these more specialized collections near the end of

this course.