kotlin-stdlib/kotlin.collections/filterIndexed

filterIndexed

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)

Returns a list containing only elements matching the given predicate.

Samples



import kotlin.test.*
fun main() { 
   //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.

@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.

Since Kotlin

1.3

Samples



import kotlin.test.*
fun main() { 
   //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.