kotlin-stdlib/kotlin.collections/AbstractMap

AbstractMap

abstract class AbstractMap<K, out V> : Map<K, V> (source)

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

The implementor is required to implement entries property, which should return read-only set of map entries.

Since Kotlin

1.1

Parameters

the type of map keys. The map is invariant in its key type.

the type of map values. The map is covariant in its value type.

Inheritors

AbstractMutableMap

Constructors

AbstractMap

protected constructor()

Properties

entries

abstract val entries: Set<Map.Entry<K, V>>

Returns a read-only Set of all key/value pairs in this map.

Since Kotlin 1.1

keys

open override val keys: Set<K>

Returns a read-only Set of all keys in this map.

Since Kotlin 1.1

size

open override val size: Int

Returns the number of key/value pairs in the map.

Since Kotlin 1.1

values

open override val values: Collection<V>

Returns a read-only Collection of all values in this map.

Since Kotlin 1.1

Functions

all

inline fun <K, V> Map<out K, V>.all(predicate: (Map.Entry<K, V>) -> Boolean): Boolean

Returns true if all entries match the given predicate.

Since Kotlin 1.0

any

fun <K, V> Map<out K, V>.any(): Boolean

Returns true if map has at least one entry.

Since Kotlin 1.0

inline fun <K, V> Map<out K, V>.any(predicate: (Map.Entry<K, V>) -> Boolean): Boolean

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

Since Kotlin 1.0

asIterable

inline fun <K, V> Map<out K, V>.asIterable(): Iterable<Map.Entry<K, V>>

Creates an Iterable instance that wraps the original map returning its entries when being iterated.

Since Kotlin 1.0

asSequence

fun <K, V> Map<out K, V>.asSequence(): Sequence<Map.Entry<K, V>>

Creates a Sequence instance that wraps the original map returning its entries when being iterated.

Since Kotlin 1.0

contains

inline operator fun <K, V> Map<out K, V>.contains(key: K): Boolean

Checks if the map contains the given key.

Since Kotlin 1.0

containsKey

open override fun containsKey(key: K): Boolean

Returns true if the map contains the specified key.

Since Kotlin 1.1

containsKey

inline fun <K> Map<out K, *>.containsKey(key: K): Boolean

Returns true if the map contains the specified key.

Since Kotlin 1.0

containsValue

open override fun containsValue(value: @UnsafeVariance V): Boolean

Returns true if the map maps one or more keys to the specified value.

Since Kotlin 1.1

containsValue

inline fun <K, V> Map<K, V>.containsValue(value: V): Boolean

Returns true if the map maps one or more keys to the specified value.

Since Kotlin 1.0

count

inline fun <K, V> Map<out K, V>.count(): Int

Returns the number of entries in this map.

Since Kotlin 1.0

inline fun <K, V> Map<out K, V>.count(predicate: (Map.Entry<K, V>) -> Boolean): Int

Returns the number of entries matching the given predicate.

Since Kotlin 1.0

equals

open operator override fun equals(other: Any?): Boolean

Compares this map with other instance with the ordered structural equality.

Since Kotlin 1.1

filter

inline fun <K, V> Map<out K, V>.filter(predicate: (Map.Entry<K, V>) -> Boolean): Map<K, V>

Returns a new map containing all key-value pairs matching the given predicate.

Since Kotlin 1.0

filterKeys

inline fun <K, V> Map<out K, V>.filterKeys(predicate: (K) -> Boolean): Map<K, V>

Returns a map containing all key-value pairs with keys matching the given predicate.

Since Kotlin 1.0

filterNot

inline fun <K, V> Map<out K, V>.filterNot(predicate: (Map.Entry<K, V>) -> Boolean): Map<K, V>

Returns a new map containing all key-value pairs not matching the given predicate.

Since Kotlin 1.0

filterNotTo

inline fun <K, V, M : MutableMap<in K, in V>> Map<out K, V>.filterNotTo(destination: M, predicate: (Map.Entry<K, V>) -> Boolean): M

Appends all entries not matching the given predicate into the given destination.

Since Kotlin 1.0

filterTo

inline fun <K, V, M : MutableMap<in K, in V>> Map<out K, V>.filterTo(destination: M, predicate: (Map.Entry<K, V>) -> Boolean): M

Appends all entries matching the given predicate into the mutable map given as destination parameter.

Since Kotlin 1.0

filterValues

inline fun <K, V> Map<out K, V>.filterValues(predicate: (V) -> Boolean): Map<K, V>

Returns a map containing all key-value pairs with values matching the given predicate.

Since Kotlin 1.0

firstNotNullOf

inline fun <K, V, R : Any> Map<out K, V>.firstNotNullOf(transform: (Map.Entry<K, V>) -> R?): R

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

Since Kotlin 1.5

firstNotNullOfOrNull

inline fun <K, V, R : Any> Map<out K, V>.firstNotNullOfOrNull(transform: (Map.Entry<K, V>) -> R?): R?

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

Since Kotlin 1.5

flatMap

inline fun <K, V, R> Map<out K, V>.flatMap(transform: (Map.Entry<K, V>) -> Iterable<R>): List<R>

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

Since Kotlin 1.0

@JvmName(name = "flatMapSequence")

inline fun <K, V, R> Map<out K, V>.flatMap(transform: (Map.Entry<K, V>) -> Sequence<R>): List<R>

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

Since Kotlin 1.4

flatMapTo

inline fun <K, V, R, C : MutableCollection<in R>> Map<out K, V>.flatMapTo(destination: C, transform: (Map.Entry<K, V>) -> Iterable<R>): C

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

Since Kotlin 1.0

@JvmName(name = "flatMapSequenceTo")

inline fun <K, V, R, C : MutableCollection<in R>> Map<out K, V>.flatMapTo(destination: C, transform: (Map.Entry<K, V>) -> Sequence<R>): C

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

Since Kotlin 1.4

forEach

inline fun <K, V> Map<out K, V>.forEach(action: (Map.Entry<K, V>) -> Unit)

Performs the given action on each entry.

Since Kotlin 1.0

get

open operator override fun get(key: K): V?

Returns the value corresponding to the given key, or null if such a key is not present in the map.

Since Kotlin 1.1

get

inline operator fun <K, V> Map<out K, V>.get(key: K): V?

Returns the value corresponding to the given key, or null if such a key is not present in the map.

Since Kotlin 1.0

getOrDefault

open fun getOrDefault(key: K, defaultValue: V): V

Returns the value corresponding to the given key, or defaultValue if such a key is not present in the map.

Since Kotlin 1.1

getOrDefault

inline fun <K, V> Map<out K, V>.getOrDefault(key: K, defaultValue: V): V

Returns the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key.

Since Kotlin 1.2

getOrElse

inline fun <K, V> Map<K, V>.getOrElse(key: K, defaultValue: () -> V): V

Returns the value for the given key if the value is present and not null. Otherwise, returns the result of the defaultValue function.

Since Kotlin 1.0

getValue

fun <K, V> Map<K, V>.getValue(key: K): V

Returns the value for the given key or throws an exception if there is no such key in the map.

Since Kotlin 1.1

inline operator fun <V, V1 : V> Map<in String, V>.getValue(thisRef: Any?, property: KProperty<*>): V1

Returns the value of the property for the given object from this read-only map.

Since Kotlin 1.0

hashCode

open override fun hashCode(): Int

Returns the hash code value for this map.

Since Kotlin 1.1

isEmpty

open override fun isEmpty(): Boolean

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

Since Kotlin 1.1

isNotEmpty

inline fun <K, V> Map<out K, V>.isNotEmpty(): Boolean

Returns true if this map is not empty.

Since Kotlin 1.0

isNullOrEmpty

inline fun <K, V> Map<out K, V>?.isNullOrEmpty(): Boolean

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

Since Kotlin 1.3

iterator

inline operator fun <K, V> Map<out K, V>.iterator(): Iterator<Map.Entry<K, V>>

Returns an Iterator over the entries in the Map.

Since Kotlin 1.0

map

inline fun <K, V, R> Map<out K, V>.map(transform: (Map.Entry<K, V>) -> R): List<R>

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

Since Kotlin 1.0

mapKeys

inline fun <K, V, R> Map<out K, V>.mapKeys(transform: (Map.Entry<K, V>) -> R): Map<R, V>

Returns a new Map with entries having the keys obtained by applying the transform function to each entry in this Map and the values of this map.

Since Kotlin 1.0

mapKeysTo

inline fun <K, V, R, M : MutableMap<in R, in V>> Map<out K, V>.mapKeysTo(destination: M, transform: (Map.Entry<K, V>) -> R): M

Populates the given destination map with entries having the keys obtained by applying the transform function to each entry in this Map and the values of this map.

Since Kotlin 1.0

mapNotNull

inline fun <K, V, R : Any> Map<out K, V>.mapNotNull(transform: (Map.Entry<K, V>) -> R?): List<R>

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

Since Kotlin 1.0

mapNotNullTo

inline fun <K, V, R : Any, C : MutableCollection<in R>> Map<out K, V>.mapNotNullTo(destination: C, transform: (Map.Entry<K, V>) -> R?): C

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

Since Kotlin 1.0

mapTo

inline fun <K, V, R, C : MutableCollection<in R>> Map<out K, V>.mapTo(destination: C, transform: (Map.Entry<K, V>) -> R): C

Applies the given transform function to each entry of the original map and appends the results to the given destination.

Since Kotlin 1.0

mapValues

inline fun <K, V, R> Map<out K, V>.mapValues(transform: (Map.Entry<K, V>) -> R): Map<K, R>

Returns a new map with entries having the keys of this map and the values obtained by applying the transform function to each entry in this Map.

Since Kotlin 1.0

mapValuesTo

inline fun <K, V, R, M : MutableMap<in K, in R>> Map<out K, V>.mapValuesTo(destination: M, transform: (Map.Entry<K, V>) -> R): M

Populates the given destination map with entries having the keys of this map and the values obtained by applying the transform function to each entry in this Map.

Since Kotlin 1.0

maxBy

@JvmName(name = "maxByOrThrow")

inline fun <K, V, R : Comparable<R>> Map<out K, V>.maxBy(selector: (Map.Entry<K, V>) -> R): Map.Entry<K, V>

Returns the first entry yielding the largest value of the given function.

Since Kotlin 1.7

inline fun <K, V, R : Comparable<R>> Map<out K, V>.~~maxBy~~(selector: (Map.Entry<K, V>) -> R): Map.Entry<K, V>?

Since Kotlin 1.0

maxByOrNull

inline fun <K, V, R : Comparable<R>> Map<out K, V>.maxByOrNull(selector: (Map.Entry<K, V>) -> R): Map.Entry<K, V>?

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

Since Kotlin 1.4

maxOf

inline fun <K, V, R : Comparable<R>> Map<out K, V>.maxOf(selector: (Map.Entry<K, V>) -> R): R

inline fun <K, V> Map<out K, V>.maxOf(selector: (Map.Entry<K, V>) -> Double): Double

inline fun <K, V> Map<out K, V>.maxOf(selector: (Map.Entry<K, V>) -> Float): Float

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

Since Kotlin 1.4

maxOfOrNull

inline fun <K, V, R : Comparable<R>> Map<out K, V>.maxOfOrNull(selector: (Map.Entry<K, V>) -> R): R?

inline fun <K, V> Map<out K, V>.maxOfOrNull(selector: (Map.Entry<K, V>) -> Double): Double?

inline fun <K, V> Map<out K, V>.maxOfOrNull(selector: (Map.Entry<K, V>) -> Float): Float?

Returns the largest value among all values produced by selector function applied to each entry in the map or null if there are no entries.

Since Kotlin 1.4

maxOfWith

inline fun <K, V, R> Map<out K, V>.maxOfWith(comparator: Comparator<in R>, selector: (Map.Entry<K, V>) -> R): R

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

Since Kotlin 1.4

maxOfWithOrNull

inline fun <K, V, R> Map<out K, V>.maxOfWithOrNull(comparator: Comparator<in R>, selector: (Map.Entry<K, V>) -> R): R?

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

Since Kotlin 1.4

maxWith

@JvmName(name = "maxWithOrThrow")

inline fun <K, V> Map<out K, V>.maxWith(comparator: Comparator<in Map.Entry<K, V>>): Map.Entry<K, V>

Returns the first entry having the largest value according to the provided comparator.

Since Kotlin 1.7

inline fun <K, V> Map<out K, V>.~~maxWith~~(comparator: Comparator<in Map.Entry<K, V>>): Map.Entry<K, V>?

Since Kotlin 1.0

maxWithOrNull

inline fun <K, V> Map<out K, V>.maxWithOrNull(comparator: Comparator<in Map.Entry<K, V>>): Map.Entry<K, V>?

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

Since Kotlin 1.4

minBy

@JvmName(name = "minByOrThrow")

inline fun <K, V, R : Comparable<R>> Map<out K, V>.minBy(selector: (Map.Entry<K, V>) -> R): Map.Entry<K, V>

Returns the first entry yielding the smallest value of the given function.

Since Kotlin 1.7

inline fun <K, V, R : Comparable<R>> Map<out K, V>.~~minBy~~(selector: (Map.Entry<K, V>) -> R): Map.Entry<K, V>?

Since Kotlin 1.0

minByOrNull

inline fun <K, V, R : Comparable<R>> Map<out K, V>.minByOrNull(selector: (Map.Entry<K, V>) -> R): Map.Entry<K, V>?

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

Since Kotlin 1.4

minOf

inline fun <K, V, R : Comparable<R>> Map<out K, V>.minOf(selector: (Map.Entry<K, V>) -> R): R

inline fun <K, V> Map<out K, V>.minOf(selector: (Map.Entry<K, V>) -> Double): Double

inline fun <K, V> Map<out K, V>.minOf(selector: (Map.Entry<K, V>) -> Float): Float

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

Since Kotlin 1.4

minOfOrNull

inline fun <K, V, R : Comparable<R>> Map<out K, V>.minOfOrNull(selector: (Map.Entry<K, V>) -> R): R?

inline fun <K, V> Map<out K, V>.minOfOrNull(selector: (Map.Entry<K, V>) -> Double): Double?

inline fun <K, V> Map<out K, V>.minOfOrNull(selector: (Map.Entry<K, V>) -> Float): Float?

Returns the smallest value among all values produced by selector function applied to each entry in the map or null if there are no entries.

Since Kotlin 1.4

minOfWith

inline fun <K, V, R> Map<out K, V>.minOfWith(comparator: Comparator<in R>, selector: (Map.Entry<K, V>) -> R): R

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

Since Kotlin 1.4

minOfWithOrNull

inline fun <K, V, R> Map<out K, V>.minOfWithOrNull(comparator: Comparator<in R>, selector: (Map.Entry<K, V>) -> R): R?

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

Since Kotlin 1.4

minus

operator fun <K, V> Map<out K, V>.minus(key: K): Map<K, V>

Returns a map containing all entries of the original map except the entry with the given key.

Since Kotlin 1.1

operator fun <K, V> Map<out K, V>.minus(keys: Array<out K>): Map<K, V>

Returns a map containing all entries of the original map except those entries the keys of which are contained in the given keys array.

Since Kotlin 1.1

operator fun <K, V> Map<out K, V>.minus(keys: Iterable<K>): Map<K, V>

Returns a map containing all entries of the original map except those entries the keys of which are contained in the given keys collection.

Since Kotlin 1.1

operator fun <K, V> Map<out K, V>.minus(keys: Sequence<K>): Map<K, V>

Returns a map containing all entries of the original map except those entries the keys of which are contained in the given keys sequence.

Since Kotlin 1.1

minWith

@JvmName(name = "minWithOrThrow")

inline fun <K, V> Map<out K, V>.minWith(comparator: Comparator<in Map.Entry<K, V>>): Map.Entry<K, V>

Returns the first entry having the smallest value according to the provided comparator.

Since Kotlin 1.7

fun <K, V> Map<out K, V>.~~minWith~~(comparator: Comparator<in Map.Entry<K, V>>): Map.Entry<K, V>?

Since Kotlin 1.0

minWithOrNull

inline fun <K, V> Map<out K, V>.minWithOrNull(comparator: Comparator<in Map.Entry<K, V>>): Map.Entry<K, V>?

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

Since Kotlin 1.4

none

fun <K, V> Map<out K, V>.none(): Boolean

Returns true if the map has no entries.

Since Kotlin 1.0

inline fun <K, V> Map<out K, V>.none(predicate: (Map.Entry<K, V>) -> Boolean): Boolean

Returns true if no entries match the given predicate.

Since Kotlin 1.0

orEmpty

inline fun <K, V> Map<K, V>?.orEmpty(): Map<K, V>

Returns the Map if its not null, or the empty Map otherwise.

Since Kotlin 1.0

plus

operator fun <K, V> Map<out K, V>.plus(pairs: Array<out Pair<K, V>>): Map<K, V>

Creates a new read-only map by replacing or adding entries to this map from a given array of key-value pairs.

Since Kotlin 1.0

operator fun <K, V> Map<out K, V>.plus(pair: Pair<K, V>): Map<K, V>

Creates a new read-only map by replacing or adding an entry to this map from a given key-value pair.

Since Kotlin 1.0

operator fun <K, V> Map<out K, V>.plus(pairs: Iterable<Pair<K, V>>): Map<K, V>

Creates a new read-only map by replacing or adding entries to this map from a given collection of key-value pairs.

Since Kotlin 1.0

operator fun <K, V> Map<out K, V>.plus(map: Map<out K, V>): Map<K, V>

Creates a new read-only map by replacing or adding entries to this map from another map.

Since Kotlin 1.0

operator fun <K, V> Map<out K, V>.plus(pairs: Sequence<Pair<K, V>>): Map<K, V>

Creates a new read-only map by replacing or adding entries to this map from a given sequence of key-value pairs.

Since Kotlin 1.0

toList

fun <K, V> Map<out K, V>.toList(): List<Pair<K, V>>

Returns a List containing all key-value pairs.

Since Kotlin 1.0

toMap

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

Returns a new read-only map containing all key-value pairs from the original map.

Since Kotlin 1.1

fun <K, V, M : MutableMap<in K, in V>> Map<out K, V>.toMap(destination: M): M

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

Since Kotlin 1.1

toMutableMap

fun <K, V> Map<out K, V>.toMutableMap(): MutableMap<K, V>

Returns a new mutable map containing all key-value pairs from the original map.

Since Kotlin 1.1

toProperties

inline fun Map<String, String>.toProperties(): Properties

Converts this Map to a Properties object.

Since Kotlin 1.0

toSortedMap

fun <K : Comparable<K>, V> Map<out K, V>.toSortedMap(): SortedMap<K, V>

Converts this Map to a SortedMap. The resulting SortedMap determines the equality and order of keys according to their natural sorting order.

Since Kotlin 1.0

fun <K, V> Map<out K, V>.toSortedMap(comparator: Comparator<in K>): SortedMap<K, V>

Converts this Map to a SortedMap. The resulting SortedMap determines the equality and order of keys according to the sorting order provided by the given comparator.

Since Kotlin 1.0

toString

open override fun toString(): String

Since Kotlin 1.1

withDefault

fun <K, V> Map<K, V>.withDefault(defaultValue: (key: K) -> V): Map<K, V>

Returns a wrapper of this read-only map, having the implicit default value provided with the specified function defaultValue.

Since Kotlin 1.0

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