first-steps 6 min

Lists: Keeping Groups of Things

What if you need to store not just one value, but a whole collection of them? A list of names, a set of scores, a shopping cart? That's exactly what list is for.

start:
    list colors = ["red", "green", "blue"]

    print(colors.length().toString())
    print(colors[0])

    colors.add("yellow")
    print(colors.length().toString())

    iterate color in colors
        print(color)

3
red
4
red
green
blue
yellow

list means this list can only hold strings. Use list for whole numbers, list for decimals.

You can also start with an empty list and build it up:

start:
    list scores
    scores.add(85)
    scores.add(92)
    scores.add(78)

    print("Total scores: {scores.length()}")
    print(scores.contains(92).toString())

Total scores: 3
true

colors[0] gives you the first item — lists start counting at zero, not one. First item is always at position 0, second at 1, and so on.

Quick recap

Declare with list — for example list or list
Add items with .add(value)
Access by position with list[0] — first item is index 0
.length() returns how many items are in the list
.contains(value) checks if something is in the list
Use iterate item in list to loop through everything