3 ms·scala> List(1,2,3).flatMap(n => List(n, n*2)) res7: List[Int] = List(1, 2, 2, 4, 3, 6)by fizx 15y agoscala> List(1,2,3).flatMap(n => List(n, n*2)) res7: List[Int] = List(1, 2, 2, 4, 3, 6)