在Scala中使用条件实现嵌套循环

Question

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")
  }
}

Answer 1

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")
)

Answer 2

Edit: whoops, you print for each i . In that case:

for (i <- 1 until 10 by 2) {
  if (!(1 until 10 by 3).exists(_ == i)) println("no intercept")
}

In this case you don't actually need the condition, though: the contains method will check what you want checked in the inner loop.

for (i <- 1 until 10 by 2) {
  if (!(1 until 10 by 3).contains(i)) println("no intercept")
}