mapExample.swift

let intArray = [0, 1, 2, 3, 4]

let mappedStrings = intArray.map { (number) -> String in
  return "\(number)"
}

// ^ Result: ["0", "1", "2", "3", "4"]

let squared = intArray.map { (number) -> Int in
  return number * number
}

// ^ Result: [0, 1, 4, 9, 16]