sequence

fun <T> sequence(block: suspend SequenceScope<T>.() -> Unit): Sequence<T>(source)

Builds a Sequence lazily yielding values one by one.

Since Kotlin

1.3

Samples

import kotlin.test.*

fun main() { 
   //sampleStart 
   val sequence = sequence {
    val start = 0
    // yielding a single value
    yield(start)
    // yielding an iterable
    yieldAll(1..5 step 2)
    // yielding an infinite sequence
    yieldAll(generateSequence(8) { it * 3 })
}

println(sequence.take(7).toList()) // [0, 1, 3, 5, 8, 24, 72] 
   //sampleEnd
}
xxxxxxxxxx
 
val sequence = sequence {
    val start = 0
    // yielding a single value
    yield(start)
    // yielding an iterable
    yieldAll(1..5 step 2)
    // yielding an infinite sequence
    yieldAll(generateSequence(8) { it * 3 })
}
println(sequence.take(7).toList()) // [0, 1, 3, 5, 8, 24, 72] 
Open in Playground →
Target: JVMRunning on v.2.1.20

import kotlin.test.*

fun main() { 
   //sampleStart 
   fun fibonacci() = sequence {
    var terms = Pair(0, 1)

    // this sequence is infinite
    while (true) {
        yield(terms.first)
        terms = Pair(terms.second, terms.first + terms.second)
    }
}

println(fibonacci().take(10).toList()) // [0, 1, 1, 2, 3, 5, 8, 13, 21, 34] 
   //sampleEnd
}
xxxxxxxxxx
 
fun fibonacci() = sequence {
    var terms = Pair(0, 1)
    // this sequence is infinite
    while (true) {
        yield(terms.first)
        terms = Pair(terms.second, terms.first + terms.second)
    }
}
println(fibonacci().take(10).toList()) // [0, 1, 1, 2, 3, 5, 8, 13, 21, 34] 
Open in Playground →
Target: JVMRunning on v.2.1.20

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sequence

Since Kotlin

See also

Samples