在Scala中将for循环增加2

Question

如何在Java中将循环增加2等同于此：

for (int i = 0; i < max; i+=2)

现在我在Scala有：

for (a <- 0 to max)

对于事实max将始终是平等的。我不知道如何在每个循环中将计数器增加到2。

Answer 1

尝试for (a <- 0 until max by 2)

Answer 2

请注意to和until之间的区别。使用严格的i < max，您需要直到。

val max = 10

scala> for(i <- 0 until max by 2)
     | println(i)
0
2
4
6
8

scala> for(i <- 0 to max by 2)
     | println(i)
0
2
4
6
8
10

Answer 3

这样你就可以像sc one一样使用scala for循环。

object Example extends App {
    for(i <-0 to 20 by 2) {
        println("Value of i = "+ i)
    }
}

<强>输出

Value of i = 0
Value of i = 2
Value of i = 4
Value of i = 6
Value of i = 8
Value of i = 10
Value of i = 12
Value of i = 14
Value of i = 16
Value of i = 18
Value of i = 20

Answer 4

不出所料容易：

scala> for (a <- 0 until 10 by 2) yield a
// Vector(0, 2, 4, 6, 8, 10)

Answer 5

for (a <- 0 to max by 2) yield a

Answer 6

当然

(0 until max by 2)  foreach {...}

就足够了。