今夜才发现耍猴的太多
问题描述
如何在 scala switch 语句中执行一个 case 块开始执行另一个 case 块.(在 java 中:没有中断的情况).
How can I do in scala switch statement which after performing one case block start perform another case block. (in java: cases without break).
switch(step) {
case 0: do something;
case 1: do something more;
case 2: etc...;
break;
default: do something else;
}
感谢您的帮助！
推荐答案
万一不能使用0 |1 |2 您可以使用操作列表作为解决方法，如下所示:
In case you can't use 0 | 1 | 2 you could use a list of actions as workaround like this:
def switch[T](i: T)(actions: (T, () => Unit)*)(default: => Unit) = {
val acts = actions.dropWhile(_._1 != i).map{_._2}
if (acts.isEmpty) default
else acts.foreach{_()}
}
def myMethod(i: Int): Unit =
switch(i)(
0 -> {() => println("do 0")},
1 -> {() => println("do 1")},
2 -> {() =>
println("do 2")
return // instead of break
},
3 -> {() => println("do 3")}
)(default = println("do default"))
myMethod(1)
// do 1
// do 2
myMethod(3)
// do 3
myMethod(5)
// do default
