Scala flatten List

Question

I want to write a function that flats a List.

object Flat {
  def flatten[T](list: List[T]): List[T] = list match {
    case Nil => Nil
    case head :: N         


        

Answer 1

You don't need to nest your match statements. Instead do the matching in place like so:

  def flatten(xs: List[Any]): List[Any] = xs match {
    case Nil => Nil
    case (head: List[_]) :: tail => flatten(head) ++ flatten(tail)
    case head :: tail => head :: flatten(tail)
  }