List PatternMatching

object PatternMatching {
  def main(args: Array[String]): Unit = {
    val x = List(1, 2, 3, 4, 5) match {
      case ::(x, ::(2, ::(4, _)))        => x
      case Nil                           => 42
      case ::(x, ::(y, ::(3, ::(4, _)))) => x + y
      case ::(h, t)                      => h + t.sum
      case _                             => 101
    }
    println(x)
  }
}

 

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