kotlin-stdlib/kotlin.collections/MutableMap

MutableMap

interface MutableMap<K, V> : Map<K, V> (source)

A modifiable collection that holds pairs of objects (keys and values) and supports efficiently retrieving the value corresponding to each key. Map keys are unique; the map holds only one value for each key.

Since Kotlin

1.0

Parameters

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

the type of map values. The mutable map is invariant in its value type.

Inheritors

AbstractMutableMap

HashMap

LinkedHashMap

Types

MutableEntry

interface MutableEntry<K, V> : Map.Entry<K, V>

Represents a key/value pair held by a MutableMap.

Since Kotlin 1.0

Properties

entries

abstract override val entries: MutableSet<MutableMap.MutableEntry<K, V>>

Returns a MutableSet of all key/value pairs in this map.

Since Kotlin 1.0

keys

abstract override val keys: MutableSet<K>

Returns a MutableSet of all keys in this map.

Since Kotlin 1.0

size

abstract val size: Int

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

Since Kotlin 1.0

values

abstract override val values: MutableCollection<V>

Returns a MutableCollection of all values in this map. Note that this collection may contain duplicate values.

Since Kotlin 1.0

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

clear

abstract fun clear()

Removes all elements from this map.

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

abstract fun containsKey(key: K): Boolean

Returns true if the map contains the specified key.

Since Kotlin 1.0

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

abstract fun containsValue(value: V): Boolean

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

Since Kotlin 1.0

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

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

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

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

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

abstract operator 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 1.0

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, or the result of the defaultValue function if there was no entry for the given key.

Since Kotlin 1.0

getOrPut

inline fun <K, V> MutableMap<K, V>.getOrPut(key: K, defaultValue: () -> V): V

Returns the value for the given key. If the key is not found in the map, calls the defaultValue function, puts its result into the map under the given key and returns it.

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

@JvmName(name = "getVar")

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

Returns the value of the property for the given object from this mutable map.

Since Kotlin 1.0

isEmpty

abstract fun isEmpty(): Boolean

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

Since Kotlin 1.0

isNotEmpty

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

Returns true if this map is not empty.

Since Kotlin 1.0

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

@JvmName(name = "mutableIterator")

inline operator fun <K, V> MutableMap<K, V>.iterator(): MutableIterator<MutableMap.MutableEntry<K, V>>

Returns a MutableIterator over the mutable entries in the MutableMap.

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

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

maxWith

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

Since Kotlin 1.0

minBy

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

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

minusAssign

inline operator fun <K, V> MutableMap<K, V>.minusAssign(key: K)

Removes the entry with the given key from this mutable map.

Since Kotlin 1.1

inline operator fun <K, V> MutableMap<K, V>.minusAssign(keys: Array<out K>)

Removes all entries the keys of which are contained in the given keys array from this mutable map.

Since Kotlin 1.1

inline operator fun <K, V> MutableMap<K, V>.minusAssign(keys: Iterable<K>)

Removes all entries the keys of which are contained in the given keys collection from this mutable map.

Since Kotlin 1.1

inline operator fun <K, V> MutableMap<K, V>.minusAssign(keys: Sequence<K>)

Removes all entries from the keys of which are contained in the given keys sequence from this mutable map.

Since Kotlin 1.1

minWith

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

Since Kotlin 1.0

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

plusAssign

inline operator fun <K, V> MutableMap<in K, in V>.plusAssign(pairs: Array<out Pair<K, V>>)

Appends or replaces all pairs from the given array of pairs in this mutable map.

Since Kotlin 1.0

inline operator fun <K, V> MutableMap<in K, in V>.plusAssign(pair: Pair<K, V>)

Appends or replaces the given pair in this mutable map.

Since Kotlin 1.0

inline operator fun <K, V> MutableMap<in K, in V>.plusAssign(pairs: Iterable<Pair<K, V>>)

Appends or replaces all pairs from the given collection of pairs in this mutable map.

Since Kotlin 1.0

inline operator fun <K, V> MutableMap<in K, in V>.plusAssign(map: Map<K, V>)

Appends or replaces all entries from the given map in this mutable map.

Since Kotlin 1.0

inline operator fun <K, V> MutableMap<in K, in V>.plusAssign(pairs: Sequence<Pair<K, V>>)

Appends or replaces all pairs from the given sequence of pairs in this mutable map.

Since Kotlin 1.0

put

abstract fun put(key: K, value: V): V?

Associates the specified value with the specified key in the map.

Since Kotlin 1.0

putAll

abstract fun putAll(from: Map<out K, V>)

Updates this map with key/value pairs from the specified map from.

Since Kotlin 1.0

putAll

fun <K, V> MutableMap<in K, in V>.putAll(pairs: Array<out Pair<K, V>>)

Puts all the given pairs into this MutableMap with the first component in the pair being the key and the second the value.

Since Kotlin 1.0

fun <K, V> MutableMap<in K, in V>.putAll(pairs: Iterable<Pair<K, V>>)

Puts all the elements of the given collection into this MutableMap with the first component in the pair being the key and the second the value.

Since Kotlin 1.0

fun <K, V> MutableMap<in K, in V>.putAll(pairs: Sequence<Pair<K, V>>)

Puts all the elements of the given sequence into this MutableMap with the first component in the pair being the key and the second the value.

Since Kotlin 1.0

remove

abstract fun remove(key: K): V?

Removes the specified key and its corresponding value from this map.

Since Kotlin 1.0

open fun remove(key: K, value: V): Boolean

Removes the entry for the specified key only if it is mapped to the specified value.

Since Kotlin 1.1

remove

inline fun <K, V> MutableMap<out K, V>.remove(key: K): V?

Removes the specified key and its corresponding value from this map.

Since Kotlin 1.0

inline fun <K, V> MutableMap<out K, out V>.remove(key: K, value: V): Boolean

Removes the entry for the specified key only if it is currently mapped to the specified value.

Since Kotlin 1.2

set

inline operator fun <K, V> MutableMap<K, V>.set(key: K, value: V)

Allows to use the index operator for storing values in a mutable map.

Since Kotlin 1.0

setValue

inline operator fun <V> MutableMap<in String, in V>.setValue(thisRef: Any?, property: KProperty<*>, value: V)

Stores the value of the property for the given object in this mutable map.

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

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

@JvmName(name = "withDefaultMutable")

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

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

Since Kotlin 1.0

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