Kotlin continue

In this article, you will learn how to use continue construct and continue labels in Kotlin.

Sometimes it is useful to force an early iteration of a loop. That is, you might want to continue running the loop but stop processing the remaining code in its body for this particular iteration. In such case we can use continue statement.

Kotlin continue example

The continue statement is used to skip the iteration of the nearest enclosing loop (for, while, and do…while loop).

Basically, continue is used to repeat the loop for a specific condition. It skips the remaining statements and continues with the next iteration of the loop.

Syntax

Syntax of continue in for loop:

for (iteration through iterator) {
    //codes
    if (test-expression) {
        continue
    }
    //codes
}

If test-expression is evaluated to true, continue statement is executed which skips the remaining statements inside the loop and continues with the next iteration of the loop.

Example

The below program will print even numbers between 1 to 10.

fun main(args: Array<String>) {

    for (n in 1..10) {

        if (n % 2 != 0)
            continue

        print(" $n ")

    }
}

Output

2  4  6  8  10

Example explained:

In the above example, when n = { 1, 3, 5, 7, 9 } :

• If condition ( n % 2 ! = 0 ) is checked, yields true.Then, continue statement is executed, which skips the execution of print(” $n “) statement.

Kotlin continue example in nested loop

fun main(args: Array<String>) {

     for (i in 1..3) {
        for (j in 1..2) {
            println("Before continue,i = $i; j = $j")
            if (i == 2) {
                continue
            }
            println("i = $i; j = $j")
        }
    }
}

Before continue,i = 1; j = 1
i = 1; j = 1
Before continue,i = 1; j = 2
i = 1; j = 2
Before continue,i = 2; j = 1
Before continue,i = 2; j = 2
Before continue,i = 3; j = 1
i = 3; j = 1
Before continue,i = 3; j = 2
i = 3; j = 2

In the above example, when i = 2 :

• If condition ( i == 2 ) is checked, yields true.Then, continue statement is executed, which skips the execution of println(“i = $i; j = $j”) statement and passes the control to inner for-loop for further iteration.

Kotlin Labeled continue example

In Kotlin, labeled continue is used to skip the iteration of the desired loop when certain condition is satisfied. It can be done with the help of labels.

Label starts with an identifier which is followed by ‘ : ‘. e.g.- inner@ , outer@ etc.

Syntax

Syntax of labeled continue in for loop:

outer@ for(iteration through iterator) {
    // code
    inner@ for(iteration through iterator) {
    // code
    if(condition for continue) {
    continue@outer
      }
   }
}

Example

fun main(args: Array<String>) {

    label@ for (i in 1..5) {
        for (j in 1..2) {
            if (i > 2) {
                continue@label
            }
            println("i = $i; j = $j")
        }
    }
}

Output

i = 1; j = 1
i = 1; j = 2
i = 2; j = 1
i = 2; j = 2

Example explained:

In the above example, when i = { 3, 4, 5 } :

• If condition ( i > 2 ) is checked, yields true.Then, continue@label is executed, which skips the execution of println(“i = $i; j = $j”) statement and passes the control to the desired loop marked with label label@ for further iteration.