scala - 如何将以下 var Scala 代码转换为 vals？

Question

var exit: String = expensiveOperation
if (exit.contains(...)) exit = somethingElse

关键是我只想打电话

昂贵的操作

一次，因为它消耗了许多时钟周期

Answer 1

如果你不想暴露其他 val ，做内联:

val exit = {
  val result = expensiveOperation
  if (result.contains(...)) somethingElse
  else result
}

或者，如果你喜欢

val exit = expensiveOperation match {
  case res if res.contains(...) => somethingElse
  case res if res.contains(...) => somethingBetter
  // ...
  case res => res
}