# Comp 101 Array Examples

## Practice with Arrays

Now that we're familiar with the concept of arrays, let's practice using them with a couple more caveats.

Let's start with a style of problem that will become very familiar to us as we get more and more comfortable with arrays: the while loop through the array!

``````let films: string[] = ["Coco", "Black Panther", "Call Me By Your Name"];
let i: number = 0;
while (i < films.length) {
print("Wow, I can't wait to see " + films[i]);
i++;
}``````

The above code is as simple as it looks -- we declare and initialize an array of strings called films, declare and initialize a number i that will keep track of where we are in the array, and loop through our array using a while loop!

Our console will show the following printed:

Wow, I can't wait to see Coco
Wow, I can't wait to see Black Panther
Wow, I can't wait to see Call Me By Your Name

Let's move on to something a little bit tougher. What if we only want to access the even indices (or in other words, where i is even) of an array?

``````let films: string[] = ["Coco", "Black Panther", "Call Me By Your Name"];
let i: number = 0;
while (i < films.length) {
if (i % 2 === 0) {
print("Wow, I can't wait to see " + films[i]);
}
i++;
}``````

Now that we've added an if-statement of i % 2 === 0, we will print the concatenated statement only when i is even. The array is unchanged, however, how we access items in the array is now different than before.

Our console shows:

Wow, I can't wait to see Coco
Wow,  I can't wait to see Call Me By Your Name

Remember, array's indices start with 0 -- so Coco's index is 0, which is even, and Black Panther's index is 1, which is odd.

Let's continue with something a little more challenging...

``````    let goodFilms = ["Coco", "Black Panther", "Call Me By Your Name"];
let haveSeen = [true, true, false];

let alert: string = "Hey! You really should see ";
let i: number = 0;

while(i < goodFilms.length) {
if (haveSeen[i]) {