kotlin-stdlib/kotlin.sequences/partition

partition

inline fun <T> Sequence<T>.partition(predicate: (T) -> Boolean): Pair<List<T>, List<T>>(source)

Splits the original sequence into pair of lists, where first list contains elements for which predicate yielded true, while second list contains elements for which predicate yielded false.

The operation is terminal.

Since Kotlin

1.0

Samples

import kotlin.test.*

fun main() { 
   //sampleStart 
   fun fibonacci(): Sequence<Int> {
    // fibonacci terms
    // 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, ...
    return generateSequence(Pair(0, 1), { Pair(it.second, it.first + it.second) }).map { it.first }
}

val (even, odd) = fibonacci().take(10).partition { it % 2 == 0 }

println(even) // [0, 2, 8, 34]
println(odd) // [1, 1, 3, 5, 13, 21] 
   //sampleEnd
}