Tuples are ordered lists of values. In Swift, you can group related elements together as a tuple, reducing the need to depend on complex types, objects, and immutable arrays.
Listing 8-1 shows how you would declare a tuple for a rectangle.
Listing 8-1. Declaring Tuples
let rectangle1 = (0, 0, 200, 100)
In Listing 8-1, you use the let keyword to declare a constant and give the constant the name rectangle1. After the assignment operator (=), you supply a comma-separated list of values enclosed in parentheses.
The value of rectangle1 from Listing 8-1 would be (0, 0, 200, 100).
For greater clarity, you can annotate each value in the tuple list as shown in Listing 8-2.
Listing 8-2. Annotated Tuple
var rectangle2 = (x:0, y:0, width:200, ...