'break' and 'continue' in forEach in Kotlin

Kotlin Mobile DevelopmentApps/Applications

In Kotlin, we have three types of structural jump expressions: "break", "return", and "continue". In this article, we will see how break and continue work in Kotliln.

  • Break - This is a keyword that helps in terminating an iteration, once a given condition is met, while traversing through a collection.

  • Continue - This keyword helps to continue the iteration once a condition is fulfilled.

In Kotlin, we cannot explicitly use break and continue statements explicitly inside a forEach loop, but we can simulate the same action. In this example, we will see how to do it.

Example: Return at labels :: directly to the caller

In this example, we will see how to stop the execution in the current loop and move back the compiler execution to the caller function. This is the equivalent of break.

fun main(args: Array<String>) {
   myFun()
   println("Welcome to TutorialsPoint")
}

fun myFun() {
   listOf(1, 2, 3, 4, 5).forEach {

      // break this iteration when
      // the condition is satisfied and
      // jump back to the calling function
      if (it == 3) return
      println(it)
   }
    println("This line won't be executed." + "It will be directly jump out" + "to the calling function, i.e., main()")
}

Output

Once we execute the above piece of code, it will terminate the execution of the function myFun() and return to the calling function, that is, main(), once the value of the iteration index to 3.

1
2
Welcome to TutorialsPoint

Example: Return at labels :: local return to the caller

In the above example, if we want to stop the loop execution only for a specific condition, then we can implement a local return to the caller. In this example, we will see how we can implement the same. This is the equivalent of "continue".

fun main(args: Array<String>) {
   myFun()
   println("Welcome to TutorialsPoint")
}

fun myFun() {
   listOf(1, 2, 3, 4, 5).forEach ca@{
      // break this iteration when the condition
      // is satisfied and continue with the flow
      if (it == 3) return@ca
      println(it)
   }
   println("This line will be executed
" + "because we are locally returing
" + "the execution to the forEach block again") }

Output

It will generate the following output

1
2
4
5
This line will be executed because we are locally returning the execution to the forEach block again
Welcome to TutorialsPoint
raja
Updated on 23-Nov-2021 06:48:01

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