filter

Common
JVM
JS
Native
1.0
inline fun <T> Array<out T>.filter(
    predicate: (T) -> Boolean
): List<T>

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inline fun ByteArray.filter(
    predicate: (Byte) -> Boolean
): List<Byte>

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inline fun ShortArray.filter(
    predicate: (Short) -> Boolean
): List<Short>

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inline fun IntArray.filter(
    predicate: (Int) -> Boolean
): List<Int>

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inline fun LongArray.filter(
    predicate: (Long) -> Boolean
): List<Long>

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inline fun FloatArray.filter(
    predicate: (Float) -> Boolean
): List<Float>

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inline fun DoubleArray.filter(
    predicate: (Double) -> Boolean
): List<Double>

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inline fun BooleanArray.filter(
    predicate: (Boolean) -> Boolean
): List<Boolean>

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inline fun CharArray.filter(
    predicate: (Char) -> Boolean
): List<Char>

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inline fun <T> Iterable<T>.filter(
    predicate: (T) -> Boolean
): List<T>

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@ExperimentalUnsignedTypes inline fun UIntArray.filter(
    predicate: (UInt) -> Boolean
): List<UInt>

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@ExperimentalUnsignedTypes inline fun ULongArray.filter(
    predicate: (ULong) -> Boolean
): List<ULong>

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@ExperimentalUnsignedTypes inline fun UByteArray.filter(
    predicate: (UByte) -> Boolean
): List<UByte>

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@ExperimentalUnsignedTypes inline fun UShortArray.filter(
    predicate: (UShort) -> Boolean
): List<UShort>

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Returns a list containing only elements matching the given predicate.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val numbers: List<Int> = listOf(1, 2, 3, 4, 5, 6, 7)
val evenNumbers = numbers.filter { it % 2 == 0 }
val notMultiplesOf3 = numbers.filterNot { number -> number % 3 == 0 }

println(evenNumbers) // [2, 4, 6]
println(notMultiplesOf3) // [1, 2, 4, 5, 7]
//sampleEnd
}
Common
JVM
JS
Native
1.0
inline fun <K, V> Map<out K, V>.filter(
    predicate: (Entry<K, V>) -> Boolean
): Map<K, V>

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Returns a new map containing all key-value pairs matching the given predicate.

The returned map preserves the entry iteration order of the original map.

import kotlin.test.*
import java.util.*

fun main(args: Array<String>) {
//sampleStart
val originalMap = mapOf("key1" to 1, "key2" to 2, "key3" to 3)

val filteredMap = originalMap.filter { it.value < 2 }

println(filteredMap) // {key1=1}
// original map has not changed
println(originalMap) // {key1=1, key2=2, key3=3}

val nonMatchingPredicate: ((Map.Entry<String, Int>)) -> Boolean = { it.value == 0 }
val emptyMap = originalMap.filter(nonMatchingPredicate)
println(emptyMap) // {}
//sampleEnd
}