kotlin-stdlib / kotlin.collections / filterIndexed

filterIndexed

Common
JVM
JS
Native
1.0
inline fun <T> Array<out T>.filterIndexed(
    predicate: (index: Int, T) -> Boolean
): List<T>
(source)
inline fun ByteArray.filterIndexed(
    predicate: (index: Int, Byte) -> Boolean
): List<Byte>
(source)
inline fun ShortArray.filterIndexed(
    predicate: (index: Int, Short) -> Boolean
): List<Short>
(source)
inline fun IntArray.filterIndexed(
    predicate: (index: Int, Int) -> Boolean
): List<Int>
(source)
inline fun LongArray.filterIndexed(
    predicate: (index: Int, Long) -> Boolean
): List<Long>
(source)
inline fun FloatArray.filterIndexed(
    predicate: (index: Int, Float) -> Boolean
): List<Float>
(source)
inline fun DoubleArray.filterIndexed(
    predicate: (index: Int, Double) -> Boolean
): List<Double>
(source)
inline fun BooleanArray.filterIndexed(
    predicate: (index: Int, Boolean) -> Boolean
): List<Boolean>
(source)
inline fun CharArray.filterIndexed(
    predicate: (index: Int, Char) -> Boolean
): List<Char>
(source)
inline fun <T> Iterable<T>.filterIndexed(
    predicate: (index: Int, T) -> Boolean
): List<T>
(source)
@ExperimentalUnsignedTypes inline fun UIntArray.filterIndexed(
    predicate: (index: Int, UInt) -> Boolean
): List<UInt>
(source)
@ExperimentalUnsignedTypes inline fun ULongArray.filterIndexed(
    predicate: (index: Int, ULong) -> Boolean
): List<ULong>
(source)
@ExperimentalUnsignedTypes inline fun UByteArray.filterIndexed(
    predicate: (index: Int, UByte) -> Boolean
): List<UByte>
(source)
@ExperimentalUnsignedTypes inline fun UShortArray.filterIndexed(
    predicate: (index: Int, UShort) -> Boolean
): List<UShort>
(source)

Returns a list containing only elements matching the given predicate.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val numbers: List<Int> = listOf(0, 1, 2, 3, 4, 8, 6)
val numbersOnSameIndexAsValue = numbers.filterIndexed { index, i -> index == i }

println(numbersOnSameIndexAsValue) // [0, 1, 2, 3, 4, 6]
//sampleEnd
}

Parameters

predicate - function that takes the index of an element and the element itself and returns the result of predicate evaluation on the element.