scala - 如何在scala的情况下模式匹配偶数？

Question

我有以下代码:

def myfunct(n: Int, steps: Int) = n match {
  case 1 =>  steps
  case (x) => if (x % 2 == 0) ...

反正有没有将偶数匹配逻辑移到案例中？我需要案例类吗？

如:

def myfunct(n: Int, steps: Int) = n match {
  case 1 =>  steps
  case (even number??) => ...

Answer 1

是的，它被称为守卫:

def myfunct (n: Int, steps: Int) = n match {
  case 1 => steps
  case even if n % 2 == 0 => // stuff
  case odd => // other stuff