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/Kotlin

List

Platform and version requirements: JVM (1.0), JS (1.1), Native (1.3)
interface List<out E> : Collection<E>

A generic ordered collection of elements. Methods in this interface support only read-only access to the list; read/write access is supported through the MutableList interface.

Parameters

E - the type of elements contained in the list. The list is covariant in its element type.

Properties

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

size

Returns the size of the collection.

abstract val size: Int

Functions

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

contains

Checks if the specified element is contained in this collection.

abstract fun contains(element: E): Boolean
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

containsAll

Checks if all elements in the specified collection are contained in this collection.

abstract fun containsAll(elements: Collection<E>): Boolean
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

get

Returns the element at the specified index in the list.

abstract operator fun get(index: Int): E
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

indexOf

Returns the index of the first occurrence of the specified element in the list, or -1 if the specified element is not contained in the list.

abstract fun indexOf(element: E): Int
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

isEmpty

Returns true if the collection is empty (contains no elements), false otherwise.

abstract fun isEmpty(): Boolean
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

iterator

Returns an iterator over the elements of this object.

abstract fun iterator(): Iterator<E>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

lastIndexOf

Returns the index of the last occurrence of the specified element in the list, or -1 if the specified element is not contained in the list.

abstract fun lastIndexOf(element: E): Int
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

listIterator

Returns a list iterator over the elements in this list (in proper sequence).

abstract fun listIterator(): ListIterator<E>

Returns a list iterator over the elements in this list (in proper sequence), starting at the specified index.

abstract fun listIterator(index: Int): ListIterator<E>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

subList

Returns a view of the portion of this list between the specified fromIndex (inclusive) and toIndex (exclusive). The returned list is backed by this list, so non-structural changes in the returned list are reflected in this list, and vice-versa.

abstract fun subList(fromIndex: Int, toIndex: Int): List<E>

Extension Properties

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

indices

Returns an IntRange of the valid indices for this collection.

val Collection<*>.indices: IntRange
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

lastIndex

Returns the index of the last item in the list or -1 if the list is empty.

val <T> List<T>.lastIndex: Int

Extension Functions

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

all

Returns true if all elements match the given predicate.

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

any

Returns true if collection has at least one element.

fun <T> Iterable<T>.any(): Boolean

Returns true if at least one element matches the given predicate.

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

asIterable

Returns this collection as an Iterable.

fun <T> Iterable<T>.asIterable(): Iterable<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

asReversed

Returns a reversed read-only view of the original List. All changes made in the original list will be reflected in the reversed one.

fun <T> List<T>.asReversed(): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

asSequence

Creates a Sequence instance that wraps the original collection returning its elements when being iterated.

fun <T> Iterable<T>.asSequence(): Sequence<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

associate

Returns a Map containing key-value pairs provided by transform function applied to elements of the given collection.

fun <T, K, V> Iterable<T>.associate(
    transform: (T) -> Pair<K, V>
): Map<K, V>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

associateBy

Returns a Map containing the elements from the given collection indexed by the key returned from keySelector function applied to each element.

fun <T, K> Iterable<T>.associateBy(
    keySelector: (T) -> K
): Map<K, T>

Returns a Map containing the values provided by valueTransform and indexed by keySelector functions applied to elements of the given collection.

fun <T, K, V> Iterable<T>.associateBy(
    keySelector: (T) -> K, 
    valueTransform: (T) -> V
): Map<K, V>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

associateByTo

Populates and returns the destination mutable map with key-value pairs, where key is provided by the keySelector function applied to each element of the given collection and value is the element itself.

fun <T, K, M : MutableMap<in K, in T>> Iterable<T>.associateByTo(
    destination: M, 
    keySelector: (T) -> K
): M

Populates and returns the destination mutable map with key-value pairs, where key is provided by the keySelector function and and value is provided by the valueTransform function applied to elements of the given collection.

fun <T, K, V, M : MutableMap<in K, in V>> Iterable<T>.associateByTo(
    destination: M, 
    keySelector: (T) -> K, 
    valueTransform: (T) -> V
): M
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

associateTo

Populates and returns the destination mutable map with key-value pairs provided by transform function applied to each element of the given collection.

fun <T, K, V, M : MutableMap<in K, in V>> Iterable<T>.associateTo(
    destination: M, 
    transform: (T) -> Pair<K, V>
): M
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

associateWith

Returns a Map where keys are elements from the given collection and values are produced by the valueSelector function applied to each element.

fun <K, V> Iterable<K>.associateWith(
    valueSelector: (K) -> V
): Map<K, V>
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

associateWithTo

Populates and returns the destination mutable map with key-value pairs for each element of the given collection, where key is the element itself and value is provided by the valueSelector function applied to that key.

fun <K, V, M : MutableMap<in K, in V>> Iterable<K>.associateWithTo(
    destination: M, 
    valueSelector: (K) -> V
): M
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

binarySearch

Searches this list or its range for the provided element using the binary search algorithm. The list is expected to be sorted into ascending order according to the Comparable natural ordering of its elements, otherwise the result is undefined.

fun <T : Comparable<T>> List<T?>.binarySearch(
    element: T?, 
    fromIndex: Int = 0, 
    toIndex: Int = size
): Int

Searches this list or its range for the provided element using the binary search algorithm. The list is expected to be sorted into ascending order according to the specified comparator, otherwise the result is undefined.

fun <T> List<T>.binarySearch(
    element: T, 
    comparator: Comparator<in T>, 
    fromIndex: Int = 0, 
    toIndex: Int = size
): Int

Searches this list or its range for an element for which the given comparison function returns zero using the binary search algorithm.

fun <T> List<T>.binarySearch(
    fromIndex: Int = 0, 
    toIndex: Int = size, 
    comparison: (T) -> Int
): Int
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

binarySearchBy

Searches this list or its range for an element having the key returned by the specified selector function equal to the provided key value using the binary search algorithm. The list is expected to be sorted into ascending order according to the Comparable natural ordering of keys of its elements. otherwise the result is undefined.

fun <T, K : Comparable<K>> List<T>.binarySearchBy(
    key: K?, 
    fromIndex: Int = 0, 
    toIndex: Int = size, 
    selector: (T) -> K?
): Int
Platform and version requirements: JVM (1.2), JS (1.2), Native (1.2)

chunked

Splits this collection into a list of lists each not exceeding the given size.

fun <T> Iterable<T>.chunked(size: Int): List<List<T>>

Splits this collection into several lists each not exceeding the given size and applies the given transform function to an each.

fun <T, R> Iterable<T>.chunked(
    size: Int, 
    transform: (List<T>) -> R
): List<R>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

component1

Returns 1st element from the list.

operator fun <T> List<T>.component1(): T
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

component2

Returns 2nd element from the list.

operator fun <T> List<T>.component2(): T
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

component3

Returns 3rd element from the list.

operator fun <T> List<T>.component3(): T
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

component4

Returns 4th element from the list.

operator fun <T> List<T>.component4(): T
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

component5

Returns 5th element from the list.

operator fun <T> List<T>.component5(): T
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

contains

Returns true if element is found in the collection.

operator fun <T> Iterable<T>.contains(element: T): Boolean
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

containsAll

Checks if all elements in the specified collection are contained in this collection.

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

count

Returns the number of elements matching the given predicate.

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

distinct

Returns a list containing only distinct elements from the given collection.

fun <T> Iterable<T>.distinct(): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

distinctBy

Returns a list containing only elements from the given collection having distinct keys returned by the given selector function.

fun <T, K> Iterable<T>.distinctBy(
    selector: (T) -> K
): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

drop

Returns a list containing all elements except first n elements.

fun <T> Iterable<T>.drop(n: Int): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

dropLast

Returns a list containing all elements except last n elements.

fun <T> List<T>.dropLast(n: Int): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

dropLastWhile

Returns a list containing all elements except last elements that satisfy the given predicate.

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

dropWhile

Returns a list containing all elements except first elements that satisfy the given predicate.

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

elementAt

Returns an element at the given index or throws an IndexOutOfBoundsException if the index is out of bounds of this list.

fun <T> List<T>.elementAt(index: Int): T
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

elementAtOrElse

Returns an element at the given index or the result of calling the defaultValue function if the index is out of bounds of this list.

fun <T> List<T>.elementAtOrElse(
    index: Int, 
    defaultValue: (Int) -> T
): T

Returns an element at the given index or the result of calling the defaultValue function if the index is out of bounds of this collection.

fun <T> Iterable<T>.elementAtOrElse(
    index: Int, 
    defaultValue: (Int) -> T
): T
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

elementAtOrNull

Returns an element at the given index or null if the index is out of bounds of this list.

fun <T> List<T>.elementAtOrNull(index: Int): T?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

filter

Returns a list containing only elements matching the given predicate.

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

filterIndexed

Returns a list containing only elements matching the given predicate.

fun <T> Iterable<T>.filterIndexed(
    predicate: (index: Int, T) -> Boolean
): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

filterIndexedTo

Appends all elements matching the given predicate to the given destination.

fun <T, C : MutableCollection<in T>> Iterable<T>.filterIndexedTo(
    destination: C, 
    predicate: (index: Int, T) -> Boolean
): C

filterIsInstance

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

Returns a list containing all elements that are instances of specified type parameter R.

fun <R> Iterable<*>.filterIsInstance(): List<R>
Platform and version requirements: JVM (1.0)

Returns a list containing all elements that are instances of specified class.

fun <R> Iterable<*>.filterIsInstance(
    klass: Class<R>
): List<R>

filterIsInstanceTo

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

Appends all elements that are instances of specified type parameter R to the given destination.

fun <R, C : MutableCollection<in R>> Iterable<*>.filterIsInstanceTo(
    destination: C
): C
Platform and version requirements: JVM (1.0)

Appends all elements that are instances of specified class to the given destination.

fun <C : MutableCollection<in R>, R> Iterable<*>.filterIsInstanceTo(
    destination: C, 
    klass: Class<R>
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

filterNot

Returns a list containing all elements not matching the given predicate.

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

filterNotNull

Returns a list containing all elements that are not null.

fun <T : Any> Iterable<T?>.filterNotNull(): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

filterNotNullTo

Appends all elements that are not null to the given destination.

fun <C : MutableCollection<in T>, T : Any> Iterable<T?>.filterNotNullTo(
    destination: C
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

filterNotTo

Appends all elements not matching the given predicate to the given destination.

fun <T, C : MutableCollection<in T>> Iterable<T>.filterNotTo(
    destination: C, 
    predicate: (T) -> Boolean
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

filterTo

Appends all elements matching the given predicate to the given destination.

fun <T, C : MutableCollection<in T>> Iterable<T>.filterTo(
    destination: C, 
    predicate: (T) -> Boolean
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

find

Returns the first element matching the given predicate, or null if no such element was found.

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

findLast

Returns the last element matching the given predicate, or null if no such element was found.

fun <T> List<T>.findLast(predicate: (T) -> Boolean): T?
fun <T> Iterable<T>.findLast(predicate: (T) -> Boolean): T?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

first

Returns first element.

fun <T> List<T>.first(): T

Returns the first element matching the given predicate.

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

firstOrNull

Returns the first element, or null if the list is empty.

fun <T> List<T>.firstOrNull(): T?

Returns the first element matching the given predicate, or null if element was not found.

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

flatMap

Returns a single list of all elements yielded from results of transform function being invoked on each element of original collection.

fun <T, R> Iterable<T>.flatMap(
    transform: (T) -> Iterable<R>
): List<R>
fun <T, R> Iterable<T>.flatMap(
    transform: (T) -> Sequence<R>
): List<R>
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

flatMapIndexed

Returns a single list of all elements yielded from results of transform function being invoked on each element and its index in the original collection.

fun <T, R> Iterable<T>.flatMapIndexed(
    transform: (index: Int, T) -> Iterable<R>
): List<R>
fun <T, R> Iterable<T>.flatMapIndexed(
    transform: (index: Int, T) -> Sequence<R>
): List<R>
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

flatMapIndexedTo

Appends all elements yielded from results of transform function being invoked on each element and its index in the original collection, to the given destination.

fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapIndexedTo(
    destination: C, 
    transform: (index: Int, T) -> Iterable<R>
): C
fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapIndexedTo(
    destination: C, 
    transform: (index: Int, T) -> Sequence<R>
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

flatMapTo

Appends all elements yielded from results of transform function being invoked on each element of original collection, to the given destination.

fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapTo(
    destination: C, 
    transform: (T) -> Iterable<R>
): C
fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapTo(
    destination: C, 
    transform: (T) -> Sequence<R>
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

flatten

Returns a single list of all elements from all collections in the given collection.

fun <T> Iterable<Iterable<T>>.flatten(): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

fold

Accumulates value starting with initial value and applying operation from left to right to current accumulator value and each element.

fun <T, R> Iterable<T>.fold(
    initial: R, 
    operation: (acc: R, T) -> R
): R
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

foldIndexed

Accumulates value starting with initial value and applying operation from left to right to current accumulator value and each element with its index in the original collection.

fun <T, R> Iterable<T>.foldIndexed(
    initial: R, 
    operation: (index: Int, acc: R, T) -> R
): R
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

foldRight

Accumulates value starting with initial value and applying operation from right to left to each element and current accumulator value.

fun <T, R> List<T>.foldRight(
    initial: R, 
    operation: (T, acc: R) -> R
): R
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

foldRightIndexed

Accumulates value starting with initial value and applying operation from right to left to each element with its index in the original list and current accumulator value.

fun <T, R> List<T>.foldRightIndexed(
    initial: R, 
    operation: (index: Int, T, acc: R) -> R
): R
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

forEach

Performs the given action on each element.

fun <T> Iterable<T>.forEach(action: (T) -> Unit)
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

forEachIndexed

Performs the given action on each element, providing sequential index with the element.

fun <T> Iterable<T>.forEachIndexed(
    action: (index: Int, T) -> Unit)
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

getOrElse

Returns an element at the given index or the result of calling the defaultValue function if the index is out of bounds of this list.

fun <T> List<T>.getOrElse(
    index: Int, 
    defaultValue: (Int) -> T
): T
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

getOrNull

Returns an element at the given index or null if the index is out of bounds of this list.

fun <T> List<T>.getOrNull(index: Int): T?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

groupBy

Groups elements of the original collection by the key returned by the given keySelector function applied to each element and returns a map where each group key is associated with a list of corresponding elements.

fun <T, K> Iterable<T>.groupBy(
    keySelector: (T) -> K
): Map<K, List<T>>

Groups values returned by the valueTransform function applied to each element of the original collection by the key returned by the given keySelector function applied to the element and returns a map where each group key is associated with a list of corresponding values.

fun <T, K, V> Iterable<T>.groupBy(
    keySelector: (T) -> K, 
    valueTransform: (T) -> V
): Map<K, List<V>>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

groupByTo

Groups elements of the original collection by the key returned by the given keySelector function applied to each element and puts to the destination map each group key associated with a list of corresponding elements.

fun <T, K, M : MutableMap<in K, MutableList<T>>> Iterable<T>.groupByTo(
    destination: M, 
    keySelector: (T) -> K
): M

Groups values returned by the valueTransform function applied to each element of the original collection by the key returned by the given keySelector function applied to the element and puts to the destination map each group key associated with a list of corresponding values.

fun <T, K, V, M : MutableMap<in K, MutableList<V>>> Iterable<T>.groupByTo(
    destination: M, 
    keySelector: (T) -> K, 
    valueTransform: (T) -> V
): M
Platform and version requirements: JVM (1.1), JS (1.1), Native (1.1)

groupingBy

Creates a Grouping source from a collection to be used later with one of group-and-fold operations using the specified keySelector function to extract a key from each element.

fun <T, K> Iterable<T>.groupingBy(
    keySelector: (T) -> K
): Grouping<T, K>
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

ifEmpty

Returns this array if it's not empty or the result of calling defaultValue function if the array is empty.

fun <C, R> C.ifEmpty(
    defaultValue: () -> R
): R where C : Array<*>, C : R
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

indexOf

Returns first index of element, or -1 if the list does not contain element.

fun <T> List<T>.indexOf(element: T): Int

Returns first index of element, or -1 if the collection does not contain element.

fun <T> Iterable<T>.indexOf(element: T): Int
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

indexOfFirst

Returns index of the first element matching the given predicate, or -1 if the list does not contain such element.

fun <T> List<T>.indexOfFirst(predicate: (T) -> Boolean): Int

Returns index of the first element matching the given predicate, or -1 if the collection does not contain such element.

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

indexOfLast

Returns index of the last element matching the given predicate, or -1 if the list does not contain such element.

fun <T> List<T>.indexOfLast(predicate: (T) -> Boolean): Int

Returns index of the last element matching the given predicate, or -1 if the collection does not contain such element.

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

intersect

Returns a set containing all elements that are contained by both this collection and the specified collection.

infix fun <T> Iterable<T>.intersect(
    other: Iterable<T>
): Set<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

isNotEmpty

Returns true if the collection is not empty.

fun <T> Collection<T>.isNotEmpty(): Boolean
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

isNullOrEmpty

Returns true if this nullable collection is either null or empty.

fun <T> Collection<T>?.isNullOrEmpty(): Boolean
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

joinTo

Appends the string from all the elements separated using separator and using the given prefix and postfix if supplied.

fun <T, A : Appendable> Iterable<T>.joinTo(
    buffer: A, 
    separator: CharSequence = ", ", 
    prefix: CharSequence = "", 
    postfix: CharSequence = "", 
    limit: Int = -1, 
    truncated: CharSequence = "...", 
    transform: ((T) -> CharSequence)? = null
): A
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

joinToString

Creates a string from all the elements separated using separator and using the given prefix and postfix if supplied.

fun <T> Iterable<T>.joinToString(
    separator: CharSequence = ", ", 
    prefix: CharSequence = "", 
    postfix: CharSequence = "", 
    limit: Int = -1, 
    truncated: CharSequence = "...", 
    transform: ((T) -> CharSequence)? = null
): String
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

last

Returns the last element.

fun <T> List<T>.last(): T

Returns the last element matching the given predicate.

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

lastIndexOf

Returns last index of element, or -1 if the list does not contain element.

fun <T> List<T>.lastIndexOf(element: T): Int

Returns last index of element, or -1 if the collection does not contain element.

fun <T> Iterable<T>.lastIndexOf(element: T): Int
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

lastOrNull

Returns the last element, or null if the list is empty.

fun <T> List<T>.lastOrNull(): T?

Returns the last element matching the given predicate, or null if no such element was found.

fun <T> List<T>.lastOrNull(predicate: (T) -> Boolean): T?
fun <T> Iterable<T>.lastOrNull(predicate: (T) -> Boolean): T?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

map

Returns a list containing the results of applying the given transform function to each element in the original collection.

fun <T, R> Iterable<T>.map(transform: (T) -> R): List<R>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

mapIndexed

Returns a list containing the results of applying the given transform function to each element and its index in the original collection.

fun <T, R> Iterable<T>.mapIndexed(
    transform: (index: Int, T) -> R
): List<R>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

mapIndexedNotNull

Returns a list containing only the non-null results of applying the given transform function to each element and its index in the original collection.

fun <T, R : Any> Iterable<T>.mapIndexedNotNull(
    transform: (index: Int, T) -> R?
): List<R>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

mapIndexedNotNullTo

Applies the given transform function to each element and its index in the original collection and appends only the non-null results to the given destination.

fun <T, R : Any, C : MutableCollection<in R>> Iterable<T>.mapIndexedNotNullTo(
    destination: C, 
    transform: (index: Int, T) -> R?
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

mapIndexedTo

Applies the given transform function to each element and its index in the original collection and appends the results to the given destination.

fun <T, R, C : MutableCollection<in R>> Iterable<T>.mapIndexedTo(
    destination: C, 
    transform: (index: Int, T) -> R
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

mapNotNull

Returns a list containing only the non-null results of applying the given transform function to each element in the original collection.

fun <T, R : Any> Iterable<T>.mapNotNull(
    transform: (T) -> R?
): List<R>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

mapNotNullTo

Applies the given transform function to each element in the original collection and appends only the non-null results to the given destination.

fun <T, R : Any, C : MutableCollection<in R>> Iterable<T>.mapNotNullTo(
    destination: C, 
    transform: (T) -> R?
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

mapTo

Applies the given transform function to each element of the original collection and appends the results to the given destination.

fun <T, R, C : MutableCollection<in R>> Iterable<T>.mapTo(
    destination: C, 
    transform: (T) -> R
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

maxBy

fun <T, R : Comparable<R>> Iterable<T>.maxBy(
    selector: (T) -> R
): T?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

maxByOrNull

Returns the first element yielding the largest value of the given function or null if there are no elements.

fun <T, R : Comparable<R>> Iterable<T>.maxByOrNull(
    selector: (T) -> R
): T?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

maxOf

Returns the largest value among all values produced by selector function applied to each element in the collection.

fun <T> Iterable<T>.maxOf(selector: (T) -> Double): Double
fun <T> Iterable<T>.maxOf(selector: (T) -> Float): Float
fun <T, R : Comparable<R>> Iterable<T>.maxOf(
    selector: (T) -> R
): R
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

maxOfOrNull

Returns the largest value among all values produced by selector function applied to each element in the collection or null if there are no elements.

fun <T> Iterable<T>.maxOfOrNull(
    selector: (T) -> Double
): Double?
fun <T> Iterable<T>.maxOfOrNull(
    selector: (T) -> Float
): Float?
fun <T, R : Comparable<R>> Iterable<T>.maxOfOrNull(
    selector: (T) -> R
): R?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

maxOfWith

Returns the largest value according to the provided comparator among all values produced by selector function applied to each element in the collection.

fun <T, R> Iterable<T>.maxOfWith(
    comparator: Comparator<in R>, 
    selector: (T) -> R
): R
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

maxOfWithOrNull

Returns the largest value according to the provided comparator among all values produced by selector function applied to each element in the collection or null if there are no elements.

fun <T, R> Iterable<T>.maxOfWithOrNull(
    comparator: Comparator<in R>, 
    selector: (T) -> R
): R?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

maxWith

fun <T> Iterable<T>.maxWith(comparator: Comparator<in T>): T?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

maxWithOrNull

Returns the first element having the largest value according to the provided comparator or null if there are no elements.

fun <T> Iterable<T>.maxWithOrNull(
    comparator: Comparator<in T>
): T?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

minBy

fun <T, R : Comparable<R>> Iterable<T>.minBy(
    selector: (T) -> R
): T?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

minByOrNull

Returns the first element yielding the smallest value of the given function or null if there are no elements.

fun <T, R : Comparable<R>> Iterable<T>.minByOrNull(
    selector: (T) -> R
): T?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

minOf

Returns the smallest value among all values produced by selector function applied to each element in the collection.

fun <T> Iterable<T>.minOf(selector: (T) -> Double): Double
fun <T> Iterable<T>.minOf(selector: (T) -> Float): Float
fun <T, R : Comparable<R>> Iterable<T>.minOf(
    selector: (T) -> R
): R
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

minOfOrNull

Returns the smallest value among all values produced by selector function applied to each element in the collection or null if there are no elements.

fun <T> Iterable<T>.minOfOrNull(
    selector: (T) -> Double
): Double?
fun <T> Iterable<T>.minOfOrNull(
    selector: (T) -> Float
): Float?
fun <T, R : Comparable<R>> Iterable<T>.minOfOrNull(
    selector: (T) -> R
): R?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

minOfWith

Returns the smallest value according to the provided comparator among all values produced by selector function applied to each element in the collection.

fun <T, R> Iterable<T>.minOfWith(
    comparator: Comparator<in R>, 
    selector: (T) -> R
): R
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

minOfWithOrNull

Returns the smallest value according to the provided comparator among all values produced by selector function applied to each element in the collection or null if there are no elements.

fun <T, R> Iterable<T>.minOfWithOrNull(
    comparator: Comparator<in R>, 
    selector: (T) -> R
): R?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

minus

Returns a list containing all elements of the original collection without the first occurrence of the given element.

operator fun <T> Iterable<T>.minus(element: T): List<T>

Returns a list containing all elements of the original collection except the elements contained in the given elements array.

operator fun <T> Iterable<T>.minus(
    elements: Array<out T>
): List<T>

Returns a list containing all elements of the original collection except the elements contained in the given elements collection.

operator fun <T> Iterable<T>.minus(
    elements: Iterable<T>
): List<T>

Returns a list containing all elements of the original collection except the elements contained in the given elements sequence.

operator fun <T> Iterable<T>.minus(
    elements: Sequence<T>
): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

minusElement

Returns a list containing all elements of the original collection without the first occurrence of the given element.

fun <T> Iterable<T>.minusElement(element: T): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

minWith

fun <T> Iterable<T>.minWith(comparator: Comparator<in T>): T?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

minWithOrNull

Returns the first element having the smallest value according to the provided comparator or null if there are no elements.

fun <T> Iterable<T>.minWithOrNull(
    comparator: Comparator<in T>
): T?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

none

Returns true if the collection has no elements.

fun <T> Iterable<T>.none(): Boolean

Returns true if no elements match the given predicate.

fun <T> Iterable<T>.none(predicate: (T) -> Boolean): Boolean
Platform and version requirements: JVM (1.1), JS (1.1), Native (1.1)

onEach

Performs the given action on each element and returns the collection itself afterwards.

fun <T, C : Iterable<T>> C.onEach(action: (T) -> Unit): C
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

onEachIndexed

Performs the given action on each element, providing sequential index with the element, and returns the collection itself afterwards.

fun <T, C : Iterable<T>> C.onEachIndexed(
    action: (index: Int, T) -> Unit
): C
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

orEmpty

Returns this List if it's not null and the empty list otherwise.

fun <T> List<T>?.orEmpty(): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

partition

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

fun <T> Iterable<T>.partition(
    predicate: (T) -> Boolean
): Pair<List<T>, List<T>>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

plus

Returns a list containing all elements of the original collection and then the given element.

operator fun <T> Iterable<T>.plus(element: T): List<T>
operator fun <T> Collection<T>.plus(element: T): List<T>

Returns a list containing all elements of the original collection and then all elements of the given elements array.

operator fun <T> Iterable<T>.plus(
    elements: Array<out T>
): List<T>
operator fun <T> Collection<T>.plus(
    elements: Array<out T>
): List<T>

Returns a list containing all elements of the original collection and then all elements of the given elements collection.

operator fun <T> Iterable<T>.plus(
    elements: Iterable<T>
): List<T>
operator fun <T> Collection<T>.plus(
    elements: Iterable<T>
): List<T>

Returns a list containing all elements of the original collection and then all elements of the given elements sequence.

operator fun <T> Iterable<T>.plus(
    elements: Sequence<T>
): List<T>
operator fun <T> Collection<T>.plus(
    elements: Sequence<T>
): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

plusElement

Returns a list containing all elements of the original collection and then the given element.

fun <T> Iterable<T>.plusElement(element: T): List<T>
fun <T> Collection<T>.plusElement(element: T): List<T>
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

random

Returns a random element from this collection.

fun <T> Collection<T>.random(): T

Returns a random element from this collection using the specified source of randomness.

fun <T> Collection<T>.random(random: Random): T
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

randomOrNull

Returns a random element from this collection, or null if this collection is empty.

fun <T> Collection<T>.randomOrNull(): T?

Returns a random element from this collection using the specified source of randomness, or null if this collection is empty.

fun <T> Collection<T>.randomOrNull(random: Random): T?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

reduce

Accumulates value starting with the first element and applying operation from left to right to current accumulator value and each element.

fun <S, T : S> Iterable<T>.reduce(
    operation: (acc: S, T) -> S
): S
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

reduceIndexed

Accumulates value starting with the first element and applying operation from left to right to current accumulator value and each element with its index in the original collection.

fun <S, T : S> Iterable<T>.reduceIndexed(
    operation: (index: Int, acc: S, T) -> S
): S
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

reduceIndexedOrNull

Accumulates value starting with the first element and applying operation from left to right to current accumulator value and each element with its index in the original collection.

fun <S, T : S> Iterable<T>.reduceIndexedOrNull(
    operation: (index: Int, acc: S, T) -> S
): S?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

reduceOrNull

Accumulates value starting with the first element and applying operation from left to right to current accumulator value and each element.

fun <S, T : S> Iterable<T>.reduceOrNull(
    operation: (acc: S, T) -> S
): S?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

reduceRight

Accumulates value starting with the last element and applying operation from right to left to each element and current accumulator value.

fun <S, T : S> List<T>.reduceRight(
    operation: (T, acc: S) -> S
): S
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

reduceRightIndexed

Accumulates value starting with the last element and applying operation from right to left to each element with its index in the original list and current accumulator value.

fun <S, T : S> List<T>.reduceRightIndexed(
    operation: (index: Int, T, acc: S) -> S
): S
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

reduceRightIndexedOrNull

Accumulates value starting with the last element and applying operation from right to left to each element with its index in the original list and current accumulator value.

fun <S, T : S> List<T>.reduceRightIndexedOrNull(
    operation: (index: Int, T, acc: S) -> S
): S?
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

reduceRightOrNull

Accumulates value starting with the last element and applying operation from right to left to each element and current accumulator value.

fun <S, T : S> List<T>.reduceRightOrNull(
    operation: (T, acc: S) -> S
): S?
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

requireNoNulls

Returns an original collection containing all the non-null elements, throwing an IllegalArgumentException if there are any null elements.

fun <T : Any> List<T?>.requireNoNulls(): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

reversed

Returns a list with elements in reversed order.

fun <T> Iterable<T>.reversed(): List<T>
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

runningFold

Returns a list containing successive accumulation values generated by applying operation from left to right to each element and current accumulator value that starts with initial value.

fun <T, R> Iterable<T>.runningFold(
    initial: R, 
    operation: (acc: R, T) -> R
): List<R>
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

runningFoldIndexed

Returns a list containing successive accumulation values generated by applying operation from left to right to each element, its index in the original collection and current accumulator value that starts with initial value.

fun <T, R> Iterable<T>.runningFoldIndexed(
    initial: R, 
    operation: (index: Int, acc: R, T) -> R
): List<R>
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

runningReduce

Returns a list containing successive accumulation values generated by applying operation from left to right to each element and current accumulator value that starts with the first element of this collection.

fun <S, T : S> Iterable<T>.runningReduce(
    operation: (acc: S, T) -> S
): List<S>
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

runningReduceIndexed

Returns a list containing successive accumulation values generated by applying operation from left to right to each element, its index in the original collection and current accumulator value that starts with the first element of this collection.

fun <S, T : S> Iterable<T>.runningReduceIndexed(
    operation: (index: Int, acc: S, T) -> S
): List<S>
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

scan

Returns a list containing successive accumulation values generated by applying operation from left to right to each element and current accumulator value that starts with initial value.

fun <T, R> Iterable<T>.scan(
    initial: R, 
    operation: (acc: R, T) -> R
): List<R>
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)

scanIndexed

Returns a list containing successive accumulation values generated by applying operation from left to right to each element, its index in the original collection and current accumulator value that starts with initial value.

fun <T, R> Iterable<T>.scanIndexed(
    initial: R, 
    operation: (index: Int, acc: R, T) -> R
): List<R>
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

scanReduce

fun <S, T : S> Iterable<T>.scanReduce(
    operation: (acc: S, T) -> S
): List<S>
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

scanReduceIndexed

fun <S, T : S> Iterable<T>.scanReduceIndexed(
    operation: (index: Int, acc: S, T) -> S
): List<S>

shuffled

Returns a new list with the elements of this list randomly shuffled using the specified random instance as the source of randomness.

Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)
fun <T> Iterable<T>.shuffled(random: Random): List<T>
Platform and version requirements: JVM (1.2)
fun <T> Iterable<T>.shuffled(random: Random): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

single

Returns the single element, or throws an exception if the list is empty or has more than one element.

fun <T> List<T>.single(): T

Returns the single element matching the given predicate, or throws exception if there is no or more than one matching element.

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

singleOrNull

Returns single element, or null if the list is empty or has more than one element.

fun <T> List<T>.singleOrNull(): T?

Returns the single element matching the given predicate, or null if element was not found or more than one element was found.

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

slice

Returns a list containing elements at indices in the specified indices range.

fun <T> List<T>.slice(indices: IntRange): List<T>

Returns a list containing elements at specified indices.

fun <T> List<T>.slice(indices: Iterable<Int>): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

sortedBy

Returns a list of all elements sorted according to natural sort order of the value returned by specified selector function.

fun <T, R : Comparable<R>> Iterable<T>.sortedBy(
    selector: (T) -> R?
): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

sortedByDescending

Returns a list of all elements sorted descending according to natural sort order of the value returned by specified selector function.

fun <T, R : Comparable<R>> Iterable<T>.sortedByDescending(
    selector: (T) -> R?
): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

sortedWith

Returns a list of all elements sorted according to the specified comparator.

fun <T> Iterable<T>.sortedWith(
    comparator: Comparator<in T>
): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

subtract

Returns a set containing all elements that are contained by this collection and not contained by the specified collection.

infix fun <T> Iterable<T>.subtract(
    other: Iterable<T>
): Set<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

sumBy

Returns the sum of all values produced by selector function applied to each element in the collection.

fun <T> Iterable<T>.sumBy(selector: (T) -> Int): Int
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

sumByDouble

Returns the sum of all values produced by selector function applied to each element in the collection.

fun <T> Iterable<T>.sumByDouble(
    selector: (T) -> Double
): Double

sumOf

Returns the sum of all values produced by selector function applied to each element in the collection.

Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)
fun <T> Iterable<T>.sumOf(selector: (T) -> Double): Double
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)
fun <T> Iterable<T>.sumOf(selector: (T) -> Int): Int
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)
fun <T> Iterable<T>.sumOf(selector: (T) -> Long): Long
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)
fun <T> Iterable<T>.sumOf(selector: (T) -> UInt): UInt
Platform and version requirements: JVM (1.4), JS (1.4), Native (1.4)
fun <T> Iterable<T>.sumOf(selector: (T) -> ULong): ULong
Platform and version requirements: JVM (1.4)
fun <T> Iterable<T>.sumOf(
    selector: (T) -> BigDecimal
): BigDecimal
Platform and version requirements: JVM (1.4)
fun <T> Iterable<T>.sumOf(
    selector: (T) -> BigInteger
): BigInteger
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

take

Returns a list containing first n elements.

fun <T> Iterable<T>.take(n: Int): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

takeLast

Returns a list containing last n elements.

fun <T> List<T>.takeLast(n: Int): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

takeLastWhile

Returns a list containing last elements satisfying the given predicate.

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

takeWhile

Returns a list containing first elements satisfying the given predicate.

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

toBooleanArray

Returns an array of Boolean containing all of the elements of this collection.

fun Collection<Boolean>.toBooleanArray(): BooleanArray
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toByteArray

Returns an array of Byte containing all of the elements of this collection.

fun Collection<Byte>.toByteArray(): ByteArray
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toCharArray

Returns an array of Char containing all of the elements of this collection.

fun Collection<Char>.toCharArray(): CharArray
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toCollection

Appends all elements to the given destination collection.

fun <T, C : MutableCollection<in T>> Iterable<T>.toCollection(
    destination: C
): C
Platform and version requirements: Native (1.3)

toCStringArray

Convert this list of Kotlin strings to C array of C strings, allocating memory for the array and C strings with given AutofreeScope.

fun List<String>.toCStringArray(
    autofreeScope: AutofreeScope
): CPointer<CPointerVar<ByteVar>>
Platform and version requirements: Native (1.3)

toCValues

fun <T : CPointed> List<CPointer<T>?>.toCValues(): CValues<CPointerVar<T>>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toDoubleArray

Returns an array of Double containing all of the elements of this collection.

fun Collection<Double>.toDoubleArray(): DoubleArray
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toFloatArray

Returns an array of Float containing all of the elements of this collection.

fun Collection<Float>.toFloatArray(): FloatArray
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toHashSet

Returns a new HashSet of all elements.

fun <T> Iterable<T>.toHashSet(): HashSet<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toIntArray

Returns an array of Int containing all of the elements of this collection.

fun Collection<Int>.toIntArray(): IntArray
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toList

Returns a List containing all elements.

fun <T> Iterable<T>.toList(): List<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toLongArray

Returns an array of Long containing all of the elements of this collection.

fun Collection<Long>.toLongArray(): LongArray
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toMap

Returns a new map containing all key-value pairs from the given collection of pairs.

fun <K, V> Iterable<Pair<K, V>>.toMap(): Map<K, V>

Populates and returns the destination mutable map with key-value pairs from the given collection of pairs.

fun <K, V, M : MutableMap<in K, in V>> Iterable<Pair<K, V>>.toMap(
    destination: M
): M
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toMutableSet

Returns a new MutableSet containing all distinct elements from the given collection.

fun <T> Iterable<T>.toMutableSet(): MutableSet<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toSet

Returns a Set of all elements.

fun <T> Iterable<T>.toSet(): Set<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

toShortArray

Returns an array of Short containing all of the elements of this collection.

fun Collection<Short>.toShortArray(): ShortArray
Platform and version requirements: JVM (1.0)

toSortedSet

Returns a new SortedSet of all elements.

fun <T> Iterable<T>.toSortedSet(
    comparator: Comparator<in T>
): SortedSet<T>
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

toUByteArray

Returns an array of UByte containing all of the elements of this collection.

fun Collection<UByte>.toUByteArray(): UByteArray
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

toUIntArray

Returns an array of UInt containing all of the elements of this collection.

fun Collection<UInt>.toUIntArray(): UIntArray
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

toULongArray

Returns an array of ULong containing all of the elements of this collection.

fun Collection<ULong>.toULongArray(): ULongArray
Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

toUShortArray

Returns an array of UShort containing all of the elements of this collection.

fun Collection<UShort>.toUShortArray(): UShortArray
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

union

Returns a set containing all distinct elements from both collections.

infix fun <T> Iterable<T>.union(other: Iterable<T>): Set<T>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

unzip

Returns a pair of lists, where first list is built from the first values of each pair from this collection, second list is built from the second values of each pair from this collection.

fun <T, R> Iterable<Pair<T, R>>.unzip(): Pair<List<T>, List<R>>
Platform and version requirements: Native (1.3)

waitForMultipleFutures

fun <T> Collection<Future<T>>.waitForMultipleFutures(
    millis: Int
): Set<Future<T>>
Platform and version requirements: JVM (1.2), JS (1.2), Native (1.2)

windowed

Returns a list of snapshots of the window of the given size sliding along this collection with the given step, where each snapshot is a list.

fun <T> Iterable<T>.windowed(
    size: Int, 
    step: Int = 1, 
    partialWindows: Boolean = false
): List<List<T>>

Returns a list of results of applying the given transform function to an each list representing a view over the window of the given size sliding along this collection with the given step.

fun <T, R> Iterable<T>.windowed(
    size: Int, 
    step: Int = 1, 
    partialWindows: Boolean = false, 
    transform: (List<T>) -> R
): List<R>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

withIndex

Returns a lazy Iterable that wraps each element of the original collection into an IndexedValue containing the index of that element and the element itself.

fun <T> Iterable<T>.withIndex(): Iterable<IndexedValue<T>>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

zip

Returns a list of pairs built from the elements of this collection and the other array with the same index. The returned list has length of the shortest collection.

infix fun <T, R> Iterable<T>.zip(
    other: Array<out R>
): List<Pair<T, R>>

Returns a list of values built from the elements of this collection and the other array with the same index using the provided transform function applied to each pair of elements. The returned list has length of the shortest collection.

fun <T, R, V> Iterable<T>.zip(
    other: Array<out R>, 
    transform: (a: T, b: R) -> V
): List<V>

Returns a list of pairs built from the elements of this collection and other collection with the same index. The returned list has length of the shortest collection.

infix fun <T, R> Iterable<T>.zip(
    other: Iterable<R>
): List<Pair<T, R>>

Returns a list of values built from the elements of this collection and the other collection with the same index using the provided transform function applied to each pair of elements. The returned list has length of the shortest collection.

fun <T, R, V> Iterable<T>.zip(
    other: Iterable<R>, 
    transform: (a: T, b: R) -> V
): List<V>
Platform and version requirements: JVM (1.2), JS (1.2), Native (1.2)

zipWithNext

Returns a list of pairs of each two adjacent elements in this collection.

fun <T> Iterable<T>.zipWithNext(): List<Pair<T, T>>

Returns a list containing the results of applying the given transform function to an each pair of two adjacent elements in this collection.

fun <T, R> Iterable<T>.zipWithNext(
    transform: (a: T, b: T) -> R
): List<R>

Inheritors

Platform and version requirements: JVM (1.1), JS (1.1), Native (1.1)

AbstractList

Provides a skeletal implementation of the read-only List interface.

abstract class AbstractList<out E> : 
    AbstractCollection<E>, 
    List<E>
Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

MutableList

A generic ordered collection of elements that supports adding and removing elements.

interface MutableList<E> : List<E>, MutableCollection<E>

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Licensed under the Apache License, Version 2.0.
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-list/index.html