Scala中for循环

Scala中to和util中的区别

    val to1 = 1 to 10
    val to2 = 1 to 10 by 2
    val until1 = 1 until 10
    val until2 = 1 until 10 by 2
    println(to1)
    println(to2)
    println(until1)
    println(until2)

输出结果：
Range(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
Range(1, 3, 5, 7, 9)
Range(1, 2, 3, 4, 5, 6, 7, 8, 9)
Range(1, 3, 5, 7, 9)

for循环中的判断条件

    val arr: Array[Int] = Array(0, 1, 2, 3, 4)
    for (a <- arr if a >= 1; if a >= 2){
      println(a)
    }

输出结果：
2
3
4

indices遍历集合索引

    val arr: Array[Int] = Array(1, 2, 3, 4, 5)
    for(i<- arr.indices){
      println(i)
    }

输出结果：
0
1
2
3
4

for循环中的break/continue

break

    val arr: Array[Int] = Array(1, 2, 3, 4, 5)
    for (a <- arr) {
      if (a == 3) break else println(a)
    }

输出结果：
1
2

continue

    val arr: Array[Int] = Array(1, 2, 3, 4, 5)
    for (a <- arr) {
      breakable {
        if (a == 3) break else println(a)
      }
    }

输出结果：
1
2
4
5