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How to break a loop in Scala?

Here, we will learn to break a loop. Examples and syntaxes to break the loop in Scala programming language.
Submitted by Shivang Yadav, on June 16, 2020

Loops in Scala: A loop is a statement that can execute a block of code multiple times based on some condition.

In Scala, there are three types of loops,

1. for loop
2. while loop
3. do...while loop

break a loop

To break a loop in Scala, we use the break statements as there is no direct break statement instead, there is a break method that is used to break a loop in Scala.

The break method needs to be imported using:

import scala.util.control.Breaks._

Syntax:

The following syntax is used to break a loop,

var loop = new breaks;
Loop.breakable{
	loop(){
		//loop body
		Loop.break;
	}
}

1) break a for loop

The for loop is used to execute a block of code multiple times in a program.

Example:

// Program to break a for loop in Scala

import scala.util.control._

object MyClass {
	def main(args: Array[String]) {
		var loop = new Breaks;
		loop.breakable{
			for(i <-  1 to 10){
				println(i*5); 
				// the loop will break at i = 6
				if(i == 6){
					loop.break; 
				}
			}
		}
	}
}

Output:

5
10
15
20
25
30

Description:

In the above code, we have displayed how to break a for loop using the break method. We have created a breakable block of code using the object of Breaks class, the object named loop can create a block in which the break statement is applied. In the breakable, we have a for loop which runs from 1 to 10 and returns i*5, but we have used the break statement at with condition. This condition will be true when i = 6 and the flow of code breaks out of the loop at the iteration.

2) break a while loop

The while loop in Scala is used to run a block of code multiple numbers of times. The number of executions is defined by an entry condition.

The break method can also be used to break out of a while loop.

Example:

// Program to break a while loop in Scala

import scala.util.control._

object MyClass {
	def main(args: Array[String]) {
		var loop = new Breaks;
		var i = 0;
		loop.breakable{
			while(i < 50){
				println(i)
				i+= 5
				// the loop will break at i > 30
				if(i > 30){
					loop.break; 
				}
			}
		}
	}
}

Output:

0
5
10
15
20
25
30

3) break a do...while loop

The do...while loop in Scala is used to run a block of code multiple numbers of time. The number of executions is defined by an exit condition.

The break method can also be used to break out of a do...while loop.

Example:

// Program to break a do...while loop in Scala
import scala.util.control._

object MyClass {
    def main(args: Array[String]) {
        var loop = new Breaks;
        var i = 0;
        loop.breakable{
            do{
                println(i)
                i+= 5
                // the loop will break at i > 30
                if(i > 30){
                    loop.break; 
                }
            }
            while(i < 50)
        }
    }
}

Output:

0
5
10
15
20
25
30