Ruby Arrays

Ruby has extensive coverage for arrays (sometimes called lists if you are coming from a Python background).

Arrays are for collecting information all in one place, or in a list. Arrays are sequential, which means that they don’t change order once set. Arrays are mutable (they can change items in the list).

Declaring an Array

Here is an example of an array:

scores = [14, 12, 4, 20, 19]

These scores can be for a particular person in a particular test or activity.

Items in the list are called like this:

puts scores[4]

This will return the 5th element from the array, as the first element is numbered 0 (i.e. scores[0])

Adding a new element to the array

You may want to add another new item/variable to the array. To do this you append to the array:

scores.append(5)

This will add a new score to the array and returns the whole array.

Delete from the array

There are at least two main ways that you can delete from an array. The first is to delete a particular item value from the array:

scores.delete(5)

will remove any item from the array that are equal to 5. The second is:

scores.delete_at(0) 

which removes from the positional index in the array (0 being the first element).