Arrays - Griffith-ICT/1701ICT-Creative-Coding GitHub Wiki

Last week we created a game with a single target. But what if there are multiple targets?

We use arrays to store multiple pieces of information.

In JavaScript we declare arrays using square brackets, []. We can define an empty array:

var targets = [];

or we can provide initial values:

var targets = [1, 2, 3, 4, 5];

Arrays can contain any type of value including strings:

var targets = ["star", "moon", "galaxy", "jupiter"];

We can use two arrays, one for each axis:

var targetX = [20, 40, 50, 5];
var targetY = [300, 200, 300, 5];

Our program will need to interpret corresponding locations in the array as belonging to the same target. For example the second target will have the co-ordinates (40, 200).

We can access arrays by the array index. Like pixel co-ordinates, array indices start at 0. So targetX[0] will be 20 and targetY[0] will be 300.

We can treat array elements like a normal variable, and hence we can change the value. If we want to assign a new random location to target at index 3:

targetX[3] = random(width);
targetY[3] = random(height);