Kotlin: repeat n time while condition is true

user_9727674 0
Viewed 1851

I need to repeat a piece of code a maximum of n times, but terminate the loop once a condition is false, like in the following:

val runs = 100
var ctr = 0
var condition = true

while (ctr++ < runs && condition) {
    //stuff and updates
}

Can this logic be stated more idiomatic, maybe with repeat?

kotlin conditional-statements idioms loops
3 Answers

You can nest lambdas and non-locally return to the outer one - I won't say this is pretty but it's an option:

run loop@{
    repeat(100) {
        if(!condition) return@loop
        // stuff and updates
    }
}
user_92419780

This is what I would consider an idiomatic way of doing this, lazily generate a sequence, limit to 100, stop on the first condition==true then do something if not null (i.e. condition==true)

            generateSequence {
                // do stuff per iteration
                Unit // or whatever value per iteration
            }.take(100).firstOrNull { condition }?.let {
                // on condition
            }
user_23239640 
val runs = 100
var condition = true


for(ctr in (0..runs)){
    if(condition){
        //stuff and updates
    }
}
user_132378070
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