Nonlinear Container HashSet

NOTE The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import HashSet from '@ohos.util.HashSet';

System Capabilities

SystemCapability.Utils.Lang

HashSet

Attributes

Name	Type	Readable	Writable	Description
length	number	Yes	No	Number of entries in a hash set (called container later).

constructor

constructor()

A constructor used to create a HashSet instance.

Example

let hashSet = new HashSet();

isEmpty

isEmpty(): boolean

Checks whether this container is empty (contains no entry).

Return value

Type	Description
boolean	Returns true if the container is empty; returns false otherwise.

Example

const hashSet = new HashSet();
let result = hashSet.isEmpty();

has

has(value: T): boolean

Checks whether this container contains the specified entry.

Parameters

Name	Type	Mandatory	Description
value	T	Yes	Entry to check.

Return value

Type	Description
boolean	Returns true if the specified entry is contained; returns false otherwise.

Example

let hashSet = new HashSet();
let result = hashSet.has("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
hashSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
let result1 = hashSet.has("Ahfbrgrbgnutfodgorrogorgrogofdfdf");

add

add(value: T): boolean

Adds an entry to this container.

Parameters

Name	Type	Mandatory	Description
value	T	Yes	Entry to add.

Return value

Type	Description
boolean	Returns true if the entry is added successfully; returns false otherwise.

Example

let hashSet = new HashSet();
let result = hashSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");

remove

remove(value: T): boolean

Removes an entry from this container.

Parameters

Name	Type	Mandatory	Description
value	T	Yes	Entry to remove.

Return value

Type	Description
boolean	Returns true if the entry is removed successfully; returns false otherwise.

Example

let hashSet = new HashSet();
hashSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
hashSet.add("sdfs");
let result = hashSet.remove("sdfs");

clear

clear(): void

Clears this container and sets its length to 0.

Example

let hashSet = new HashSet();
hashSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
hashSet.add("sdfs");
hashSet.clear();

values

values(): IterableIterator<T>

Obtains an iterator that contains all the values in this container.

Return value

Type	Description
IterableIterator<T>	Iterator obtained.

Example

let hashSet = new HashSet();
hashSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
hashSet.add("sdfs");
let iter = hashSet.values();
let temp = iter.next().value;
while(temp != undefined) {
  console.log("value:" + temp);
  temp = iter.next().value;
}

forEach

forEach(callbackfn: (value?: T, key?: T, set?: HashSet<T>) => void, thisArg?: Object): void

Uses a callback to traverse the entries in this container and obtain their position indexes.

Parameters

Name	Type	Mandatory	Description
callbackfn	function	Yes	Callback invoked to traverse the entries in the container.
thisArg	Object	No	Value to use when the callback is invoked.

callbackfn

Name	Type	Mandatory	Description
value	T	No	Value of the entry that is currently traversed.
key	T	No	Key of the entry that is currently traversed (same as value).
set	HashSet<T>	No	Instance that invokes the forEach method.

Example

let hashSet = new HashSet();
hashSet.add("sdfs");
hashSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
hashSet.forEach((value, key) => {
  console.log("value:" + value, key);
});

entries

entries(): IterableIterator<[T, T]>

Obtains an iterator that contains all the entries in this container.

Return value

Type	Description
IterableIterator<[T, T]>	Iterator obtained.

Example

let hashSet = new HashSet();
hashSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
hashSet.add("sdfs");
let iter = hashSet.entries();
let temp = iter.next().value;
while(temp != undefined) {
  console.log("key:" + temp[0]);
  console.log("value:" + temp[1]);
  temp = iter.next().value;
}

[Symbol.iterator]

[Symbol.iterator](): IterableIterator<T>

Obtains an iterator, each item of which is a JavaScript object.

Return value

Type	Description
IterableIterator<T>	Iterator obtained.

Example

let hashSet = new HashSet();
hashSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
hashSet.add("sdfs");

// Method 1:
for (let item of hashSet) { 
  console.log("value: " + item);
}

// Method 2:
let iter = hashSet[Symbol.iterator]();
let temp = iter.next().value;
while(temp != undefined) {
  console.log("value: " + temp);
  temp = iter.next().value;
}