Can I yield or map one element into many in Scala?

Question

val inArray = Array("a", "b", "c", "d")
// ...
val outArray = Array("a1", "a2", "a3", "b1", "b2", "b3", "c1", "c2", "c3", "d1", "d2", "d3")

How to map inArray to outArray?

The idea is to iterate through inArray yielding 3 elements (by concatenating an index in this example) from each of its elements.

Answer 1

You can do that with flatMap.

inArray.flatMap(c => (1 to 3).map(c+))