How to match for the last item in a List in Scala

The flexibility of Scala's match operator continues to amaze me.

Here's one I just found tonight. In all my match code so far, I've always had conditions for an empty list (case Nil =>) and a list with at least one item, which I usually write as case item :: moreItems =>

Tonight I needed to have a different case for when there is ONLY one item in the list. I thought, "I wonder if I can put Nil on the right-hand side of the ::?" And, sure enough, as has almost always been the case when I've asked "can match do this?", the answer was yes.

Code:

object TestingObject {
  def main(args: Array[String]) {
    isOneItemList(Nil)
    isOneItemList(List())
    isOneItemList(List("1"))
    isOneItemList(List("1", "2"))
    isOneItemList(List("1", "2", "3"))
    isOneItemList(List("1", "2", "3", "4"))
  }

  def isOneItemList(list: List[String]) : Unit = {
    println(list + " => " +
      (list match {
        case Nil => "Nope: it's empty"
        case one :: Nil => "Yep: just one"
        case one :: two :: Nil => "Nope: there's exactly two"
        case _ => "Nope: there's at least three"
      })
    )
  }
}

Output:

List() => Nope: it's empty
List() => Nope: it's empty
List(1) => Yep: just one
List(1, 2) => Nope: there's exactly two
List(1, 2, 3) => Nope: there's at least three
List(1, 2, 3, 4) => Nope: there's at least three