Kotlin for Loop with examples

The for loop in Kotlin is used to iterate or cycle though the elements of array, ranges, collections etc. In this guide, we will learn how to use for loop in Kotlin with the help of various examples.

A simple example of for loop in Kotlin

In the following example we are iterating though an integer range using for loop.

/**
 * created by Chaitanya for Beginnersbook.com
 */

package beginnersbook

fun main(args : Array<String>){

    for(n in 10..15){
        println("Loop: $n")
    }
}

Output:

Kotlin for loop using Array

In the following example we have declared an array myArray and we are displaying the elements of the array using for loop.

package beginnersbook

fun main(args : Array<String>){

    val myArray = arrayOf("ab", "bc", "cd", "da")
    for (str in myArray){
        println(str)
    }
}

Output:

ab
bc
cd
da

Kotlin for loop iterating though array indices

We can also use array indexes to iterate though the array.

/**
 * created by Chaitanya for Beginnersbook.com
 */

package beginnersbook

fun main(args : Array<String>){

    val myArray = arrayOf("Steve", "Robin", "Kate", "Lucy")
    for (n in myArray.indices){
        println("myArray[$n]: ${myArray[n]}")
    }
}

Output:

Function withIndex() in for loop

In the above example we have iterated through the array using array indices. Another way of doing the same is with the use of withIndex() function.

package beginnersbook

fun main(args : Array<String>){

    val myArray = arrayOf("Steve", "Robin", "Kate", "Lucy")
    for((index, value) in myArray.withIndex()){
        println("Value at Index $index is: $value")
    }
}

Output:

Value at Index 0 is: Steve
Value at Index 1 is: Robin
Value at Index 2 is: Kate
Value at Index 3 is: Lucy