kotlin-stdlib/kotlin.collections/[JS]MutableMap

MutableMap

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.

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.

Types

MutableEntry

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

Represents a key/value pair held by a MutableMap.

Functions

clear

abstract fun clear()

Removes all elements from this map.

containsKey

abstract fun containsKey(key: K): Boolean

Returns true if the map contains the specified key.

containsValue

abstract fun containsValue(value: V): Boolean

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

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.

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

isEmpty

abstract fun isEmpty(): Boolean

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

put

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

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

putAll

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

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

remove

abstract fun remove(key: K): V?

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

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

Properties

entries

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

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

keys

abstract override val keys: MutableSet<K>

Returns a MutableSet of all keys in this map.

size

abstract val size: Int

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

values

abstract override val values: MutableCollection<V>

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

Inheritors

AbstractMutableMap

HashMap

LinkedHashMap

Extensions

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.

getValue

@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.

iterator

@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.

minusAssign

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

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

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.

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.

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.

plusAssign

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.

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.

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.

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.

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.

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.

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.

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.

remove

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

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

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.

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.

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.

withDefault

@JvmName(name = "withDefaultMutable")

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

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