The zip function is provided by the Swift standard library and creates a sequence of pairs built out of two underlying sequences, where the elements of the i^th pair are the i^th elements of each underlying sequence.

For instance, in the following example, zip takes two arrays and creates a pair of these two arrays:

let numbers = [3, 5, 9, 10] 
let alphabeticNumbers = ["Three", "Five", "Nine", "Ten"] 

let zipped = zip(alphabeticNumbers, numbers).map { $0 } 

The value for zipped will be [("Three", 3), ("Five", 5), ("Nine", 9), ("Ten", 10)].