Interdig

This function allows you to combine two sequences by alternately selecting elements from each.

func interdig<T>(list1: [T], list2: [T]) -> [T] {

    return zip(list1, list2).reduce([], { (ac: [T], o: (T, T)) -> [T] in 

         return ac + [o.0, o.1]

    })

}

print(interdig(list1: [1, 3, 5], list2: [2, 4, 6]))

// : [1, 2, 3, 4, 5, 6]