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retainAll

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)
fun <T> MutableCollection<out T>.retainAll(
    elements: Collection<T>
): Boolean

Retains only the elements in this collection that are contained in the specified collection.

Allows to overcome type-safety restriction of retainAll that requires to pass a collection of type Collection<E>.

Return true if any element was removed from the collection, false if the collection was not modified.

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)
fun <T> MutableCollection<in T>.retainAll(
    elements: Iterable<T>
): Boolean

Retains only elements of this MutableCollection that are contained in the given elements collection.

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)
fun <T> MutableCollection<in T>.retainAll(
    elements: Array<out T>
): Boolean

Retains only elements of this MutableCollection that are contained in the given elements array.

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)
fun <T> MutableCollection<in T>.retainAll(
    elements: Sequence<T>
): Boolean

Retains only elements of this MutableCollection that are contained in the given elements sequence.

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)
fun <T> MutableIterable<T>.retainAll(
    predicate: (T) -> Boolean
): Boolean

Retains only elements of this MutableIterable that match the given predicate.

Return true if any element was removed from this collection, or false when all elements were retained and collection was not modified.

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)
fun <T> MutableList<T>.retainAll(
    predicate: (T) -> Boolean
): Boolean

Retains only elements of this MutableList that match the given predicate.

Return true if any element was removed from this collection, or false when all elements were retained and collection was not modified.

© 2010–2020 JetBrains s.r.o. and Kotlin Programming Language contributors
Licensed under the Apache License, Version 2.0.
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/retain-all.html