Java 中 return 用 Scala 表达

最新推荐文章于 2025-07-17 11:07:14 发布

最新推荐文章于 2025-07-17 11:07:14 发布 · 261 阅读

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#Scala #Java

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本文探讨了Scala中缺失break和continue关键字的问题，并提供了替代方案。通过使用find等高阶函数结合模式匹配，可以实现类似Java中return的功能。

Scala 中没有 break(2.8 中将会支持) 和 continue,的确是件纠结的事情啊~
更纠结的是，return 似乎也不能直接 work
比如 Java 里头可以这样写（虽然这样写并不好）：

for(int i = 0; i < 10; i++){
            System.out.println("i = " + i);
            if(i == 1){
                System.out.println("return at i = 1");
                return;
            }else if( i == 2){
                System.out.println("return i = 2");
                return ;
            }
       }

但是 Scala 里头怎么办列，或许换种思考的方式会更好：

(0 until 10).find{ i => 
  println("i = " + i)
  i match {
  case 1 => println("return at i = 1"); true
  case 2 => println("return at i = 2"); true
  case _ => false
}}

对于 break 和 continue，
[quote]These keywords are not included in Scala 2.7, and must be implemented in a different way. For break, the simplest thing to do is to divide your code into smaller methods and use the return to exit early. For continue, a simple approach is to place the skipped-over parts of a loop into an if.

Scala 2.8 will include break, but not continue.[/quote]