kotlin-stdlib/kotlin.collections/[JRE]Iterable

Iterable

interface Iterable<out T>

Classes that inherit from this interface can be represented as a sequence of elements that can be iterated over.

Parameters

the type of element being iterated over. The iterator is covariant in its element type.

Functions

iterator

JRE

abstract operator fun iterator(): Iterator<T>

Returns an iterator over the elements of this object.

Inheritors

MutableIterable

Collection

UIntProgression

ULongProgression

CharProgression

IntProgression

LongProgression

Extensions

all

Common

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

Returns true if all elements match the given predicate.

any

Common

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

Returns true if collection has at least one element.

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

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

asIterable

Common

inline fun <T> Iterable<T>.asIterable(): Iterable<T>

Returns this collection as an Iterable.

asSequence

Common

fun <T> Iterable<T>.asSequence(): Sequence<T>

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

associate

Common

inline fun <T, K, V> Iterable<T>.associate(transform: (T) -> Pair<K, V>): Map<K, V>

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

associateBy

Common

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

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

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

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

associateByTo

Common

inline 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 applied to each element of the given collection and value is the element itself.

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

associateTo

Common

inline fun <T, K, V, M : MutableMap<in K, in V>> Iterable<T>.associateTo(destination: M, transform: (T) -> Pair<K, V>): M

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

associateWith

Common

inline fun <K, V> Iterable<K>.associateWith(valueSelector: (K) -> V): Map<K, V>

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

associateWithTo

Common

inline fun <K, V, M : MutableMap<in K, in V>> Iterable<K>.associateWithTo(destination: M, valueSelector: (K) -> V): M

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.

average

Common

@JvmName(name = "averageOfByte")

fun Iterable<Byte>.average(): Double

@JvmName(name = "averageOfShort")

fun Iterable<Short>.average(): Double

@JvmName(name = "averageOfInt")

fun Iterable<Int>.average(): Double

@JvmName(name = "averageOfLong")

fun Iterable<Long>.average(): Double

@JvmName(name = "averageOfFloat")

fun Iterable<Float>.average(): Double

@JvmName(name = "averageOfDouble")

fun Iterable<Double>.average(): Double

Returns an average value of elements in the collection.

chunked

Common

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

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

fun <T, R> Iterable<T>.chunked(size: Int, transform: (List<T>) -> R): List<R>

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

contains

Common

operator fun <T> Iterable<T>.contains(element: T): Boolean

Returns true if element is found in the collection.

count

Common

fun <T> Iterable<T>.count(): Int

Returns the number of elements in this collection.

inline fun <T> Iterable<T>.count(predicate: (T) -> Boolean): Int

Returns the number of elements matching the given predicate.

distinct

Common

fun <T> Iterable<T>.distinct(): List<T>

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

distinctBy

Common

inline fun <T, K> Iterable<T>.distinctBy(selector: (T) -> K): List<T>

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

drop

Common

fun <T> Iterable<T>.drop(n: Int): List<T>

Returns a list containing all elements except first n elements.

dropWhile

Common

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

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

elementAt

Common

fun <T> Iterable<T>.elementAt(index: Int): T

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

elementAtOrElse

Common

fun <T> Iterable<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.

elementAtOrNull

Common

fun <T> Iterable<T>.elementAtOrNull(index: Int): T?

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

filter

Common

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

Returns a list containing only elements matching the given predicate.

filterIndexed

Common

inline fun <T> Iterable<T>.filterIndexed(predicate: (index: Int, T) -> Boolean): List<T>

Returns a list containing only elements matching the given predicate.

filterIndexedTo

Common

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

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

filterIsInstance

Common

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

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

JRE

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

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

filterIsInstanceTo

Common

inline fun <R, C : MutableCollection<in R>> Iterable<*>.filterIsInstanceTo(destination: C): C

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

JRE

fun <C : MutableCollection<in R>, R> Iterable<*>.filterIsInstanceTo(destination: C, klass: Class<R>): C

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

filterNot

Common

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

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

filterNotNull

Common

fun <T : Any> Iterable<T?>.filterNotNull(): List<T>

Returns a list containing all elements that are not null.

filterNotNullTo

Common

fun <C : MutableCollection<in T>, T : Any> Iterable<T?>.filterNotNullTo(destination: C): C

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

filterNotTo

Common

inline fun <T, C : MutableCollection<in T>> Iterable<T>.filterNotTo(destination: C, predicate: (T) -> Boolean): C

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

filterTo

Common

inline fun <T, C : MutableCollection<in T>> Iterable<T>.filterTo(destination: C, predicate: (T) -> Boolean): C

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

find

Common

inline fun <T> Iterable<T>.find(predicate: (T) -> Boolean): T?

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

findLast

Common

inline fun <T> Iterable<T>.findLast(predicate: (T) -> Boolean): T?

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

first

Common

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

Returns first element.

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

Returns the first element matching the given predicate.

firstNotNullOf

Common

inline fun <T, R : Any> Iterable<T>.firstNotNullOf(transform: (T) -> R?): R

Returns the first non-null value produced by transform function being applied to elements of this collection in iteration order, or throws NoSuchElementException if no non-null value was produced.

firstNotNullOfOrNull

Common

inline fun <T, R : Any> Iterable<T>.firstNotNullOfOrNull(transform: (T) -> R?): R?

Returns the first non-null value produced by transform function being applied to elements of this collection in iteration order, or null if no non-null value was produced.

firstOrNull

Common

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

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

inline fun <T> Iterable<T>.firstOrNull(predicate: (T) -> Boolean): T?

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

flatMap

Common

inline fun <T, R> Iterable<T>.flatMap(transform: (T) -> Iterable<R>): List<R>

@JvmName(name = "flatMapSequence")

inline fun <T, R> Iterable<T>.flatMap(transform: (T) -> Sequence<R>): List<R>

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

flatMapIndexed

Common

@JvmName(name = "flatMapIndexedIterable")

inline fun <T, R> Iterable<T>.flatMapIndexed(transform: (index: Int, T) -> Iterable<R>): List<R>

@JvmName(name = "flatMapIndexedSequence")

inline fun <T, R> Iterable<T>.flatMapIndexed(transform: (index: Int, T) -> Sequence<R>): List<R>

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.

flatMapIndexedTo

Common

@JvmName(name = "flatMapIndexedIterableTo")

inline fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapIndexedTo(destination: C, transform: (index: Int, T) -> Iterable<R>): C

@JvmName(name = "flatMapIndexedSequenceTo")

inline fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapIndexedTo(destination: C, transform: (index: Int, T) -> Sequence<R>): C

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.

flatMapTo

Common

inline fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapTo(destination: C, transform: (T) -> Iterable<R>): C

@JvmName(name = "flatMapSequenceTo")

inline fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapTo(destination: C, transform: (T) -> Sequence<R>): C

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

flatten

Common

fun <T> Iterable<Iterable<T>>.flatten(): List<T>

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

fold

Common

inline fun <T, R> Iterable<T>.fold(initial: R, operation: (R, T) -> R): R

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

foldIndexed

Common

inline fun <T, R> Iterable<T>.foldIndexed(initial: R, operation: (index: Int, R, T) -> R): R

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.

forEach

Common

inline fun <T> Iterable<T>.forEach(action: (T) -> Unit)

Performs the given action on each element.

forEachIndexed

Common

inline fun <T> Iterable<T>.forEachIndexed(action: (index: Int, T) -> Unit)

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

groupBy

Common

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

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.

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

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.

groupByTo

Common

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

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.

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

groupingBy

Common

inline fun <T, K> Iterable<T>.groupingBy(crossinline keySelector: (T) -> K): Grouping<T, K>

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.

indexOf

Common

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

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

indexOfFirst

Common

inline fun <T> Iterable<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.

indexOfLast

Common

inline fun <T> Iterable<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.

intersect

Common

infix fun <T> Iterable<T>.intersect(other: Iterable<T>): Set<T>

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

joinTo

Common

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

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

joinToString

Common

fun <T> Iterable<T>.joinToString(separator: CharSequence = ", ", prefix: CharSequence = "", postfix: CharSequence = "", limit: Int = -1, truncated: CharSequence = "...", transform: (T) -> CharSequence? = null): String

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

last

Common

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

Returns the last element.

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

Returns the last element matching the given predicate.

lastIndexOf

Common

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

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

lastOrNull

Common

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

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

inline fun <T> Iterable<T>.lastOrNull(predicate: (T) -> Boolean): T?

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

map

Common

inline fun <T, R> Iterable<T>.map(transform: (T) -> R): List<R>

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

mapIndexed

Common

inline fun <T, R> Iterable<T>.mapIndexed(transform: (index: Int, T) -> R): List<R>

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

mapIndexedNotNull

Common

inline fun <T, R : Any> Iterable<T>.mapIndexedNotNull(transform: (index: Int, T) -> R?): List<R>

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.

mapIndexedNotNullTo

Common

inline fun <T, R : Any, C : MutableCollection<in R>> Iterable<T>.mapIndexedNotNullTo(destination: C, transform: (index: Int, T) -> R?): C

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.

mapIndexedTo

Common

inline fun <T, R, C : MutableCollection<in R>> Iterable<T>.mapIndexedTo(destination: C, transform: (index: Int, T) -> R): C

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

mapNotNull

Common

inline fun <T, R : Any> Iterable<T>.mapNotNull(transform: (T) -> R?): List<R>

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

mapNotNullTo

Common

inline fun <T, R : Any, C : MutableCollection<in R>> Iterable<T>.mapNotNullTo(destination: C, transform: (T) -> R?): C

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

mapTo

Common

inline fun <T, R, C : MutableCollection<in R>> Iterable<T>.mapTo(destination: C, transform: (T) -> R): C

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

max

Common

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~fun~~ Iterable<Double>.~~max~~(): Double?

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~fun~~ Iterable<Float>.~~max~~(): Float?

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~fun~~ <T : Comparable<T>> Iterable<T>.~~max~~(): T?

maxBy

Common

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~inline~~ ~~fun~~ <T, R : Comparable<R>> Iterable<T>.~~maxBy~~(~~selector~~: (T) -> R): T?

maxByOrNull

Common

inline fun <T, R : Comparable<R>> Iterable<T>.maxByOrNull(selector: (T) -> R): T?

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

maxOf

Common

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

inline fun <T> Iterable<T>.maxOf(selector: (T) -> Float): Float

inline fun <T, R : Comparable<R>> Iterable<T>.maxOf(selector: (T) -> R): R

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

maxOfOrNull

Common

inline fun <T> Iterable<T>.maxOfOrNull(selector: (T) -> Double): Double?

inline fun <T> Iterable<T>.maxOfOrNull(selector: (T) -> Float): Float?

inline fun <T, R : Comparable<R>> Iterable<T>.maxOfOrNull(selector: (T) -> R): R?

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.

maxOfWith

Common

inline fun <T, R> Iterable<T>.maxOfWith(comparator: Comparator<in R>, selector: (T) -> R): R

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

maxOfWithOrNull

Common

inline fun <T, R> Iterable<T>.maxOfWithOrNull(comparator: Comparator<in R>, selector: (T) -> R): R?

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.

maxOrNull

Common

fun Iterable<Double>.maxOrNull(): Double?

fun Iterable<Float>.maxOrNull(): Float?

fun <T : Comparable<T>> Iterable<T>.maxOrNull(): T?

Returns the largest element or null if there are no elements.

maxWith

Common

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~fun~~ <T> Iterable<T>.~~maxWith~~(~~comparator~~: Comparator<in T>): T?

maxWithOrNull

Common

fun <T> Iterable<T>.maxWithOrNull(comparator: Comparator<in T>): T?

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

min

Common

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~fun~~ Iterable<Double>.~~min~~(): Double?

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~fun~~ Iterable<Float>.~~min~~(): Float?

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~fun~~ <T : Comparable<T>> Iterable<T>.~~min~~(): T?

minBy

Common

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~inline~~ ~~fun~~ <T, R : Comparable<R>> Iterable<T>.~~minBy~~(~~selector~~: (T) -> R): T?

minByOrNull

Common

inline fun <T, R : Comparable<R>> Iterable<T>.minByOrNull(selector: (T) -> R): T?

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

minOf

Common

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

inline fun <T> Iterable<T>.minOf(selector: (T) -> Float): Float

inline fun <T, R : Comparable<R>> Iterable<T>.minOf(selector: (T) -> R): R

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

minOfOrNull

Common

inline fun <T> Iterable<T>.minOfOrNull(selector: (T) -> Double): Double?

inline fun <T> Iterable<T>.minOfOrNull(selector: (T) -> Float): Float?

inline fun <T, R : Comparable<R>> Iterable<T>.minOfOrNull(selector: (T) -> R): R?

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.

minOfWith

Common

inline fun <T, R> Iterable<T>.minOfWith(comparator: Comparator<in R>, selector: (T) -> R): R

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

minOfWithOrNull

Common

inline fun <T, R> Iterable<T>.minOfWithOrNull(comparator: Comparator<in R>, selector: (T) -> R): R?

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.

minOrNull

Common

fun Iterable<Double>.minOrNull(): Double?

fun Iterable<Float>.minOrNull(): Float?

fun <T : Comparable<T>> Iterable<T>.minOrNull(): T?

Returns the smallest element or null if there are no elements.

minus

Common

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

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

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 array.

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 collection.

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

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

minusElement

Common

inline fun <T> Iterable<T>.minusElement(element: T): List<T>

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

minWith

Common

@DeprecatedSinceKotlin(warningSince = "1.4", errorSince = "1.5")

~~fun~~ <T> Iterable<T>.~~minWith~~(~~comparator~~: Comparator<in T>): T?

minWithOrNull

Common

fun <T> Iterable<T>.minWithOrNull(comparator: Comparator<in T>): T?

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

none

Common

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

Returns true if the collection has no elements.

inline fun <T> Iterable<T>.none(predicate: (T) -> Boolean): Boolean

Returns true if no elements match the given predicate.

partition

Common

inline fun <T> Iterable<T>.partition(predicate: (T) -> Boolean): Pair<List<T>, List<T>>

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.

plus

Common

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

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

operator fun <T> Iterable<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 array.

operator fun <T> Iterable<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 collection.

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

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

plusElement

Common

inline fun <T> Iterable<T>.plusElement(element: T): List<T>

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

reduce

Common

inline fun <S, T : S> Iterable<T>.reduce(operation: (S, T) -> S): S

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

reduceIndexed

Common

inline fun <S, T : S> Iterable<T>.reduceIndexed(operation: (index: Int, S, T) -> S): S

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.

reduceIndexedOrNull

Common

inline fun <S, T : S> Iterable<T>.reduceIndexedOrNull(operation: (index: Int, S, T) -> S): S?

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.

reduceOrNull

Common

inline fun <S, T : S> Iterable<T>.reduceOrNull(operation: (S, T) -> S): S?

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

requireNoNulls

Common

fun <T : Any> Iterable<T?>.requireNoNulls(): Iterable<T>

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

reversed

Common

fun <T> Iterable<T>.reversed(): List<T>

Returns a list with elements in reversed order.

runningFold

Common

inline fun <T, R> Iterable<T>.runningFold(initial: R, operation: (R, T) -> R): List<R>

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.

runningFoldIndexed

Common

inline fun <T, R> Iterable<T>.runningFoldIndexed(initial: R, operation: (index: Int, R, T) -> R): List<R>

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.

runningReduce

Common

inline fun <S, T : S> Iterable<T>.runningReduce(operation: (S, T) -> S): List<S>

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.

runningReduceIndexed

Common

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

scan

Common

inline fun <T, R> Iterable<T>.scan(initial: R, operation: (R, T) -> R): List<R>

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.

scanIndexed

Common

inline fun <T, R> Iterable<T>.scanIndexed(initial: R, operation: (index: Int, R, T) -> R): List<R>

shuffled

fun <T> Iterable<T>.shuffled(random: Random): List<T>

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

Common

fun <T> Iterable<T>.shuffled(): List<T>

Returns a new list with the elements of this list randomly shuffled.

single

Common

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

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

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

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

singleOrNull

Common

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

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

inline fun <T> Iterable<T>.singleOrNull(predicate: (T) -> Boolean): T?

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

sorted

Common

fun <T : Comparable<T>> Iterable<T>.sorted(): List<T>

Returns a list of all elements sorted according to their natural sort order.

sortedBy

Common

inline fun <T, R : Comparable<R>> Iterable<T>.sortedBy(crossinline selector: (T) -> R?): List<T>

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

sortedByDescending

Common

inline fun <T, R : Comparable<R>> Iterable<T>.sortedByDescending(crossinline selector: (T) -> R?): List<T>

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

sortedDescending

Common

fun <T : Comparable<T>> Iterable<T>.sortedDescending(): List<T>

Returns a list of all elements sorted descending according to their natural sort order.

sortedWith

Common

fun <T> Iterable<T>.sortedWith(comparator: Comparator<in T>): List<T>

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

subtract

Common

infix fun <T> Iterable<T>.subtract(other: Iterable<T>): Set<T>

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

sum

Common

@JvmName(name = "sumOfByte")

fun Iterable<Byte>.sum(): Int

@JvmName(name = "sumOfShort")

fun Iterable<Short>.sum(): Int

@JvmName(name = "sumOfInt")

fun Iterable<Int>.sum(): Int

@JvmName(name = "sumOfLong")

fun Iterable<Long>.sum(): Long

@JvmName(name = "sumOfFloat")

fun Iterable<Float>.sum(): Float

@JvmName(name = "sumOfDouble")

fun Iterable<Double>.sum(): Double

@JvmName(name = "sumOfUInt")

fun Iterable<UInt>.sum(): UInt

@JvmName(name = "sumOfULong")

fun Iterable<ULong>.sum(): ULong

@JvmName(name = "sumOfUByte")

fun Iterable<UByte>.sum(): UInt

@JvmName(name = "sumOfUShort")

fun Iterable<UShort>.sum(): UInt

Returns the sum of all elements in the collection.

sumBy

Common

@DeprecatedSinceKotlin(warningSince = "1.5")

~~inline~~ ~~fun~~ <T> Iterable<T>.~~sumBy~~(~~selector~~: (T) -> Int): Int

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

sumByDouble

Common

@DeprecatedSinceKotlin(warningSince = "1.5")

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

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

sumOf

@JvmName(name = "sumOfDouble")

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

@JvmName(name = "sumOfInt")

inline fun <T> Iterable<T>.sumOf(selector: (T) -> Int): Int

@JvmName(name = "sumOfLong")

inline fun <T> Iterable<T>.sumOf(selector: (T) -> Long): Long

@JvmName(name = "sumOfUInt")

inline fun <T> Iterable<T>.sumOf(selector: (T) -> UInt): UInt

@JvmName(name = "sumOfULong")

inline fun <T> Iterable<T>.sumOf(selector: (T) -> ULong): ULong

@JvmName(name = "sumOfBigDecimal")

inline fun <T> Iterable<T>.sumOf(selector: (T) -> BigDecimal): BigDecimal

@JvmName(name = "sumOfBigInteger")

inline fun <T> Iterable<T>.sumOf(selector: (T) -> BigInteger): BigInteger

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

take

Common

fun <T> Iterable<T>.take(n: Int): List<T>

Returns a list containing first n elements.

takeWhile

Common

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

Returns a list containing first elements satisfying the given predicate.

toCollection

Common

fun <T, C : MutableCollection<in T>> Iterable<T>.toCollection(destination: C): C

Appends all elements to the given destination collection.

toHashSet

Common

fun <T> Iterable<T>.toHashSet(): HashSet<T>

Returns a new HashSet of all elements.

toList

Common

fun <T> Iterable<T>.toList(): List<T>

Returns a List containing all elements.

toMap

Common

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

Returns a new map containing all 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

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

toMutableList

Common

fun <T> Iterable<T>.toMutableList(): MutableList<T>

Returns a new MutableList filled with all elements of this collection.

toMutableSet

Common

fun <T> Iterable<T>.toMutableSet(): MutableSet<T>

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

toSet

Common

fun <T> Iterable<T>.toSet(): Set<T>

Returns a Set of all elements.

toSortedSet

JRE

fun <T : Comparable<T>> Iterable<T>.toSortedSet(): SortedSet<T>

fun <T> Iterable<T>.toSortedSet(comparator: Comparator<in T>): SortedSet<T>

Returns a new SortedSet of all elements.

union

Common

infix fun <T> Iterable<T>.union(other: Iterable<T>): Set<T>

Returns a set containing all distinct elements from both collections.

unzip

Common

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

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.

windowed

Common

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

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

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.

withIndex

Common

fun <T> Iterable<T>.withIndex(): Iterable<IndexedValue<T>>

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.

zip

Common

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

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.

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

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.

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

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.

inline fun <T, R, V> Iterable<T>.zip(other: Iterable<R>, transform: (T, R) -> V): List<V>

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.

zipWithNext

Common

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

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

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

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