Question

For example suppose I have

val letters = ('a', 'b', 'c', 'd', 'e')
val numbers = (1, 2)

Is it possible to produce a list

(('a',1), ('b',2), ('c',1),('d',2),('e',1))

Answer 1

Your letters and numbers are tuples, not lists. So let’s fix that

scala> val letters = List('a', 'b', 'c', 'd', 'e')
letters: List[Char] = List(a, b, c, d, e)

scala> val numbers = List(1,2)                    
numbers: List[Int] = List(1, 2)

Now, if we zip them we don’t get the desired result

scala> letters zip numbers
res11: List[(Char, Int)] = List((a,1), (b,2))

But that suggests that if numbers were repeated infinitely then the problem would be solved

scala> letters zip (Stream continually numbers).flatten
res12: List[(Char, Int)] = List((a,1), (b,2), (c,1), (d,2), (e,1))

Unfortunately, that’s based on knowledge that numbers is shorter than letters. So to fix it all up

scala> ((Stream continually letters).flatten zip (Stream continually numbers).flatten take (letters.size max numbers.size)).toList
res13: List[(Char, Int)] = List((a,1), (b,2), (c,1), (d,2), (e,1))