Linear Container ArrayList

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 ArrayList from '@ohos.util.ArrayList';

System Capabilities

SystemCapability.Utils.Lang

ArrayList

Attributes

constructor

constructor()

A constructor used to create an ArrayList instance.

Example

let arrayList = new ArrayList();

add

add(element: T): boolean

Adds an entry at the end of this container.

Parameters

Return value

Example

let arrayList = new ArrayList();
let result = arrayList.add("a");
let result1 = arrayList.add(1);
let b = [1, 2, 3];
let result2 = arrayList.add(b);
let c = {name: "lala", age: "13"};
let result3 = arrayList.add(false);

insert

insert(element: T, index: number): void

Inserts an entry at the specified position in this container.

Parameters

Example

let arrayList = new ArrayList();
arrayList.insert("A", 0);
arrayList.insert(0, 1);
arrayList.insert(true, 2);

has

has(element: T): boolean

Checks whether this container has the specified entry.

Parameters

Return value

Example

let arrayList = new ArrayList();
let result = arrayList.has("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
arrayList.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
let result1 = arrayList.has("Ahfbrgrbgnutfodgorrogorgrogofdfdf");

getIndexOf

getIndexOf(element: T): number

Obtains the index of the first occurrence of the specified entry in this container.

Parameters

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(2);
arrayList.add(1);
arrayList.add(2);
arrayList.add(4);
let result = arrayList.getIndexOf(2);

getLastIndexOf

getLastIndexOf(element: T): number

Obtains the index of the last occurrence of the specified entry in this container.

Parameters

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(2);
arrayList.add(1);
arrayList.add(2);
arrayList.add(4);
let result = arrayList.getLastIndexOf(2);

removeByIndex

removeByIndex(index: number): T

Removes an entry with the specified position from this container.

Parameters

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(2);
arrayList.add(4);
let result = arrayList.removeByIndex(2);

remove

remove(element: T): boolean

Removes the first occurrence of the specified entry from this container.

Parameters

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
let result = arrayList.remove(2);

removeByRange

removeByRange(fromIndex: number, toIndex: number): void

Removes from this container all of the entries within a range, including the entry at the start position but not that at the end position.

Parameters

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
arrayList.removeByRange(2, 4);
arrayList.removeByRange(4, 3);
arrayList.removeByRange(2, 6);

replaceAllElements

replaceAllElements(callbackfn: (value: T, index?: number, arrlist?: ArrayList<T>) => T, thisArg?: Object): void

Replaces all entries in this container with new entries, and returns the new ones.

Parameters

callbackfn

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
arrayList.replaceAllElements((value, index) => {
  return value = 2 * value;
});
arrayList.replaceAllElements((value, index) => {
  return value = value - 2;
});

forEach

forEach(callbackfn: (value: T, index?: number, arrlist?: ArrayList<T>) => void, thisArg?: Object): void

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

Parameters

callbackfn

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
arrayList.forEach((value, index) => {
  console.log("value:" + value, index);
});

sort

sort(comparator?: (firstValue: T, secondValue: T) => number): void

Sorts entries in this container.

Parameters

comparator

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
arrayList.sort((a, b) => a - b);
arrayList.sort((a, b) => b - a);
arrayList.sort();

subArrayList

subArrayList(fromIndex: number, toIndex: number): ArrayList<T>

Obtains entries within a range in this container, including the entry at the start position but not that at the end position, and returns these entries as a new ArrayList instance.

Parameters

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
let result1 = arrayList.subArrayList(2, 4);
let result2 = arrayList.subArrayList(4, 3);
let result3 = arrayList.subArrayList(2, 6);

clear

clear(): void

Clears this container and sets its length to 0.

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
arrayList.clear();

clone

clone(): ArrayList<T>

Clones this container and returns a copy. The modification to the copy does not affect the original instance.

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
let result = arrayList.clone();

getCapacity

getCapacity(): number

Obtains the capacity of this container.

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
let result = arrayList.getCapacity();

convertToArray

convertToArray(): Array<T>

Converts this container into an array.

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
let result = arrayList.convertToArray();

isEmpty

isEmpty(): boolean

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

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
let result = arrayList.isEmpty();

increaseCapacityTo

increaseCapacityTo(newCapacity: number): void

Increases the capacity of this container.

Parameters

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
arrayList.increaseCapacityTo(2);
arrayList.increaseCapacityTo(8);

trimToCurrentLength

trimToCurrentLength(): void

Trims the capacity of this container to its current length.

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);
arrayList.trimToCurrentLength();

[Symbol.iterator]

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

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

Return value

Example

let arrayList = new ArrayList();
arrayList.add(2);
arrayList.add(4);
arrayList.add(5);
arrayList.add(4);

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

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