scala 模式匹配字符串序列中的值

Question

變量 someKey 可以是“a”、“b”或“c”。

我可以做這個：

someKey match {
    case "a" => someObjectA.execute()
    case "b" => someOther.execute()
    case "c" => someOther.execute()
    case _ => throw new IllegalArgumentException("Unknown")
}

如何壓縮此模式匹配，以便我可以檢查 someKey 是否與例如 Seq("b", "c") 以及它是否在序列中，然后將兩行模式匹配替換為一行？

編輯：

someKey match {
        case "a" => someObjectA.execute()
        case someKey if Seq("b","c").contains(someKey) => someOther.execute()
        case _ => throw new IllegalArgumentException("Unknown")
    }

Answer 1

您可以在case子句中使用“或”：

someKey match {
    case "a" => someObjectA.execute()
    case "b"|"c" => someOther.execute()
    case _ => ???
}

Answer 2

對於這種特殊情況，我可能會 go 到

// likely in some companion object so these get constructed once
val otherExecute = { () => someOther.execute() }
val keyedTasks = Map(
  "a" -> { () => someObjectA.execute() },
  "b" -> otherExecute,
  "c" -> otherExecute
)

// no idea on the result type of the execute calls?  Unit?
def someFunction(someKey: String) = {
  val resultOpt = keyedTasks.get(someKey).map(_())

  if (resultOpt.isDefined) resultOpt.get
  else throw new IllegalArgumentException("Unknown")
}