val list = List(Some(1), None, Some(3)) list.flatMap { //=> List(1, 2, 3, 6) case Some(x) => List(x, x * 2) case None => List() } list.map { //=> List(List(1, 2), List(), List(3, 6)) case Some(x) => List(x, x * 2) case None => List() } lis…