Using "Map" in Swift To Create Superset of Two Arrays

Question

Let's say I have two arrays:

let letterArray = ["a", "b", "c", "d", "e"...]
let numberArray = [1, 2, 3, 4, 5, 6, 7...]

I want to combine the two arrays so that I would get an output of

["a1", "b2", "c3", "d4", "e5"]

How would I go about doing that?

Answer 1

You can use zip(_:_:) before map:

let a = ["a", "b", "c", "d", "e"]
let b = [1, 2, 3, 4, 5]

let result = zip(a, b).map { $0 + String($1) }

print(result) // => ["a1", "b2", "c3", "d4", "e5"]

You can try this code here.

zip(_:_:) produces a custom Zip2Sequence, which has a special implmentation of the SequenceType protocol, so that it iterates pairs made from the two source collections.