Kotlin 中的多变量 For 循环 [英] For Loop with Multivariable in Kotlin

问题描述

如何在 kotlin 中仅使用一个 for 循环来执行此 java 代码?

How can I do this java code in kotlin using just one for loop?

for(int i=0, j=0; i < 6 && j < 6; i++, j+=2) {
    // code here
}

推荐答案

非常感谢 gidds 的回答

I really appreciate gidds's answer

但是还有另一种更简单的方法来为两个变量

but there is another easier way to write for in loops for two variables

for ( (i, j) in (0..6).zip(0..6 step 2)){
    println("values are: $i, $j")
}

以上代码运行正常

您还可以为三个变量轻松编写for in循环.看下面的代码.

you can also write for in loops easily for three variable. See the following code.

在这段代码中，我试图实现一个三变量系列

In this code I tried to implement a three variable series

// 1.2.3 + 2.3.4 + 3.4.5 + ... + n(n+1)(n+2)

fun main(args: Array<String>) {
    // taking int input from console
    val number: Int = readLine()!!.toInt()
    var sum: Int = 0

    // here second variable jPair becomes pair because of second nested zip
    for ( (i, jPair) in (1..number).zip((0..number + 1).zip(2..number + 2))) {
        println("values are: $i, ${jPair.first}, ${jPair.second}")

        sum += (i * jPair.first * jPair.second)
    }

    println("Series sum is: $sum")
}

现在，让我们实现四个变量 for in 循环

在下面的代码中，我试图实现一个四变量系列

In the following code I am trying to implement a four variable series

// 1.3.5.7 + 3.5.7.9 + 5.7.9.11 + ... + n(n+2)(n+4)(n+6)

fun main(args: Array<String>) {
    // taking int input from console
    val number: Int = readLine()!!.toInt()
    var sum: Int = 0

    // here second variable iPair becomes pair because of first nested zip
    // here second variable jPair becomes pair because of second nested zip
    for ( (iPair, jPair) in ((1..number step 2).zip(3..number + 2 step 2)).zip((5..number + 4 step 2).zip(7..number + 6 step 2))) {
        println("values are: ${iPair.first}, ${iPair.second}, ${jPair.first}, ${jPair.second}")

        sum += (iPair.first * iPair.second * jPair.first * jPair.second)
    }

    println("Series sum is: $sum")
}

通过这种方式，我们可以轻松实现多个变量 for in 循环.

This way we can implement multiple variable for in loops easily.

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