在Scala中使用条件实现嵌套循环(Implement nested loop with condition in Scala)

在Scala中使用条件实现嵌套循环(Implement nested loop with condition in Scala)

在Scala中实现以下代码的惯用方式是什么？

for (int i = 1; i < 10; i+=2) { // i = 1, 3, 5, 7, 9 bool intercept = false; for (int j = 1; j < 10; j+=3) { // j = 1, 4, 7 if (i==j) intercept = true } if (!intercept) { System.out.println("no intercept") } }

What is an idiomatic way to implement the following code in Scala?

for (int i = 1; i < 10; i+=2) { // i = 1, 3, 5, 7, 9 bool intercept = false; for (int j = 1; j < 10; j+=3) { // j = 1, 4, 7 if (i==j) intercept = true } if (!intercept) { System.out.println("no intercept") } }

最满意答案

你可以使用Range和朋友：

if (((1 until 10 by 2) intersect (1 until 10 by 3)).isEmpty) System.out.println("no intercept")

这不涉及一个嵌套循环（在标题中提到），但它是在Scala中获得相同结果的更习惯方式。

编辑：正如Rex Kerr指出的那样，上面的版本不会每次都打印这条消息，但是下面是这样的：

(1 until 10 by 2) filterNot (1 until 10 by 3 contains _) foreach ( _ => println("no intercept") )

You can use Range and friends:

if (((1 until 10 by 2) intersect (1 until 10 by 3)).isEmpty) System.out.println("no intercept")

This doesn't involve a nested loop (which you refer to in the title), but it is a much more idiomatic way to get the same result in Scala.

Edit: As Rex Kerr points out, the version above doesn't print the message each time, but the following does:

(1 until 10 by 2) filterNot (1 until 10 by 3 contains _) foreach ( _ => println("no intercept") )