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Data Structures
Access by Index

Here’s something interesting about arrays: each element in the array has what’s called an index. The first element is at index `0`, the next is at index `1`, the following is at index `2`, and so on. We can access elements of the array directly through these numbers using brackets, like so:

``````array = [5, 7, 9, 2, 0]
array[2]
# returns "9", since "9"
# is at index 2``````

The diagram below shows how these indices work for our sample array, `[5, 7, 9, 2, 0]`. The first element has index `0`, the next has `1`, the next has `2`, and so on.

``````        +---+---+---+---+---+
array   | 5 | 7 | 9 | 2 | 0 |
+---+---+---+---+---+
index     0   1   2   3   4``````

(This is a bit of an oversimplification, but it gets the idea across for now).

We can access the `i`th element of an array called `array` by putting the index in square brackets, like so: `array[i]`. `array[0]` gets the first element, `array[1]` gets the second element, and so on. This is called access by index.

Instructions

1.

Use square bracket notation to `print` the third value of `demo_array` to the console.

Remember that the third value is at index `2`, not at index `3`. We start counting indices from zero.