Borrows this iterable as a lazy sequence without traversing or copying it. Each traversal requests a new source iterator; later mutations and invalidation follow the iterable's own contract. Wrappers and iterators use ordinary managed heap quotas.

contains

abstract operator fun contains(p0: E?): Boolean

Checks whether this collection contains an element equal to element.

contains

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

Checks whether this iterable has an element equal to element.

containsAll

abstract fun containsAll(p0: Collection<*>?): Boolean

filter

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

Returns a list containing elements matching predicate, in their original iteration order.

filterNotNull

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

Returns a list of non-null elements in their original iteration order.

filterTo

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

Appends matching elements to destination in iteration order.

find

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

Returns the first matching element, or null when no element matches predicate.

first

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

Returns the first element, throwing NoSuchElementException when empty.

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

Returns the first matching element, throwing NoSuchElementException when no element matches.

firstOrNull

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

Returns the first element, or null when this iterable is empty.

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

Returns the first element, or null when this list is empty.

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

Returns the first matching element, or null when no element matches predicate.

fold

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

Accumulates elements in iteration order.

forEach

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

Calls action for each element in iteration order.

forEachIndexed

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

Calls action for each element and its zero-based index in iteration order.

get

abstract operator fun get(index: Int): E

Returns the element at index.

getOrNull

fun <T> List<T>.getOrNull(index: Int): T?

Returns the element at index, or null when the index is outside this list.

indexOf

abstract fun indexOf(element: E): Int

Returns the index of the first element equal to element.

indexOf

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

Returns the index of the first equal element, or -1 when no element matches.

isEmpty

abstract fun isEmpty(): Boolean

Checks whether this collection has no elements.

isNotEmpty

fun <T> Collection<T>.isNotEmpty(): Boolean

Checks whether this collection contains at least one element.

iterator

abstract operator fun iterator(): Iterator<E>

Returns an iterator over this iterable's elements.

lastIndexOf

abstract fun lastIndexOf(element: E): Int

Returns the index of the last element equal to element.

lastIndexOf

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

Returns the index of the last equal element, or -1 when no element matches.

lastOrNull

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

Returns the last element, or null when this iterable is empty.

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

Returns the last element, or null when this list is empty.

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

Returns the last matching element after traversing this iterable in iteration order.

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

Returns the last element satisfying predicate, or null when no element matches.

listIterator

abstract fun listIterator(): ListIterator<E?>?

abstract fun listIterator(p0: Int): ListIterator<E?>?

map

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

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

Returns a list containing transform applied once to each element in iteration order.

mapNotNull

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

Applies transform once per element in iteration order and retains only non-null results.

mapNotNullTo

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

Appends non-null transformed elements to destination in iteration order.

mapTo

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

Appends transformed elements to destination in iteration order.

none

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

Returns true when no element matches predicate.

removeAll

abstract fun removeAll(p0: Collection<*>?): Boolean

retainAll

abstract fun retainAll(p0: Collection<*>?): Boolean

subList

abstract fun subList(p0: Int, p1: Int): List<E?>?

sum

fun Iterable<Byte>.sum(): Int

Numeric accumulation traverses once in iteration order without an intermediate collection. Empty iterables return positive numeric zero. Integer arithmetic wraps at the result width; Float/Double addition retains ordinary rounding, infinities and NaN. Byte/Short widen to Int; UByte/UShort widen to UInt. Iterator failures propagate unchanged.

fun Iterable<Double>.sum(): Double

fun Iterable<Float>.sum(): Float

fun Iterable<Int>.sum(): Int

fun Iterable<Long>.sum(): Long

fun Iterable<Short>.sum(): Int

fun Iterable<UByte>.sum(): UInt

fun Iterable<UInt>.sum(): UInt

fun Iterable<ULong>.sum(): ULong

fun Iterable<UShort>.sum(): UInt

sumOf

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

Sums selector once per element in iteration order, returning Double zero when empty. No collection is allocated; selector/iterator exceptions and inline non-local returns propagate. Addition retains ordinary Double rounding, infinities and NaN.

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

Sums selector once per element in iteration order, returning Int zero when empty. No collection is allocated; selector/iterator exceptions and inline non-local returns propagate. Addition uses ordinary wrapping Int arithmetic.

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

Sums selector once per element in iteration order, returning Long zero when empty. No collection is allocated; selector/iterator exceptions and inline non-local returns propagate. Addition uses ordinary wrapping Long arithmetic.

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

Sums selector once per element in iteration order, returning UInt zero when empty. No collection is allocated; selector/iterator exceptions and inline non-local returns propagate. Addition uses ordinary wrapping UInt arithmetic.

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

Sums selector once per element in iteration order, returning ULong zero when empty. No collection is allocated; selector/iterator exceptions and inline non-local returns propagate. Addition uses ordinary wrapping ULong arithmetic.