EnumEntries
A specialized immutable implementation of List interface that contains all enum entries of the specified enum type E. EnumEntries contains all enum entries in the order they are declared in the source code, consistently with the corresponding Enum.ordinal values.
An instance of this interface can be obtained from EnumClass.entries
property or with enumEntries function.
Implementation note
All basic operations, such as contains
and indexOf
, are executed in constant time and are likely to be
faster than regular ArrayList<E>
counterparts.
Extension Properties
indices
Returns an IntRange of the valid indices for this collection.
val Collection<*>.indices: IntRange
Extension Functions
associateBy
Returns a Map containing the elements from the given collection indexed by the key returned from keySelector function applied to each element.
Returns a Map containing the values provided by valueTransform and indexed by keySelector functions applied to elements of the given collection.
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
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
associateWith
Returns a Map where keys are elements from the given collection and values are produced by the valueSelector function applied to each element.
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
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 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
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
component1
Returns 1st element from the list.
operator fun <T> List<T>.component1(): T
component2
Returns 2nd element from the list.
operator fun <T> List<T>.component2(): T
component3
Returns 3rd element from the list.
operator fun <T> List<T>.component3(): T
component4
Returns 4th element from the list.
operator fun <T> List<T>.component4(): T
component5
Returns 5th element from the list.
operator fun <T> List<T>.component5(): T
containsAll
Checks if all elements in the specified collection are contained in this collection.
fun <T> Collection<T>.containsAll(
elements: Collection<T>
): Boolean
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 collection.
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 list.
fun <T> List<T>.elementAtOrElse(
index: Int,
defaultValue: (Int) -> T
): T
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
filterIsInstanceTo
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
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
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
firstNotNullOf
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.
fun <T, R : Any> Iterable<T>.firstNotNullOf(
transform: (T) -> R?
): R
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.
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
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
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
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.
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
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
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.
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
indexOf
indexOfFirst
indexOfLast
isNotEmpty
Returns true
if the collection is not empty.
fun <T> Collection<T>.isNotEmpty(): Boolean
isNullOrEmpty
Returns true
if this nullable collection is either null or empty.
fun <T> Collection<T>?.isNullOrEmpty(): Boolean
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
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
lastIndexOf
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
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
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
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
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?
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
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?
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
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?
maxWith
Returns the first element having the largest value according to the provided comparator.
fun <T> Iterable<T>.maxWith(comparator: Comparator<in T>): T
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?
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?
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
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?
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
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?
minus
Returns a list containing all elements of the original collection without the first occurrence of the given element.
Returns a list containing all elements of the original collection except the elements contained in the given elements array.
Returns a list containing all elements of the original collection except the elements contained in the given elements collection.
minWith
Returns the first element having the smallest value according to the provided comparator.
fun <T> Iterable<T>.minWith(comparator: Comparator<in T>): T
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?
plus
Returns a list containing all elements of the original collection and then the given element.
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> 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> Collection<T>.plus(
elements: Iterable<T>
): List<T>
plusElement
Returns a list containing all elements of the original collection and then the given element.
fun <T> Collection<T>.plusElement(element: T): List<T>
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
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?
runningFoldIndexed
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.
scanIndexed
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>
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>
sortedWith
Returns a list of all elements sorted according to the specified comparator.
fun <T> Iterable<T>.sortedWith(
comparator: Comparator<in T>
): List<T>
sumOf
toCollection
Appends all elements to the given destination collection.
fun <T, C : MutableCollection<in T>> Iterable<T>.toCollection(
destination: C
): C
toMap
Returns a new map containing all key-value pairs from the given collection of pairs.
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
toMutableSet
Returns a new MutableSet containing all distinct elements from the given collection.
fun <T> Iterable<T>.toMutableSet(): MutableSet<T>
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.
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>>
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.
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.
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.
zipWithNext
Returns a list of pairs of each two adjacent elements in this collection.