@ohos.util.PlainArray (Nonlinear Container PlainArray)

PlainArray stores key-value (KV) pairs. Each key must be unique, be of the number type, and have only one value.

PlainArray is based on generics and uses a lightweight structure. Keys in the array are searched using binary search and are mapped to values in other arrays.

Both PlainArray and LightWeightMap are used to store KV pairs in the lightweight structure. However, the key type of PlainArray can only be number.

Recommended use case: Use PlainArray when you need to store KV pairs whose keys are of the number type.

This topic uses the following to identify the use of generics: - T: Type

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 PlainArray from '@ohos.util.PlainArray';  

PlainArray

Attributes

System capability: SystemCapability.Utils.Lang

constructor

constructor()

A constructor used to create a PlainArray instance.

System capability: SystemCapability.Utils.Lang

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();

isEmpty

isEmpty(): boolean

Checks whether this container is empty.

System capability: SystemCapability.Utils.Lang

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

const plainArray: PlainArray<string> = new PlainArray();
let result = plainArray.isEmpty();

has

has(key: number): boolean

Checks whether this container contains the specified key.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
let result = plainArray.has(1);

get

get(key: number): T

Obtains the value of the specified key in this container.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let result = plainArray.get(1);

getIndexOfKey

getIndexOfKey(key: number): number

Obtains the index of the first occurrence of an element with the specified key in this container.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let result = plainArray.getIndexOfKey(2);

getIndexOfValue

getIndexOfValue(value: T): number

Obtains the index of the first occurrence of an element with the specified value in this container.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let result = plainArray.getIndexOfValue("squirrel");

getKeyAt

getKeyAt(index: number): number

Obtains the key of the element at the specified position in this container.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let result = plainArray.getKeyAt(1);

getValueAt

getValueAt(index: number): T

Obtains the value of an element at the specified position in this container.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let result = plainArray.getValueAt(1);

clone

clone(): PlainArray<T>

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

System capability: SystemCapability.Utils.Lang

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let newPlainArray = plainArray.clone();

add

add(key: number, value: T): void

Adds an element to this container.

System capability: SystemCapability.Utils.Lang

Parameters

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");

remove

remove(key: number): T

Removes an element with the specified key from this container.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let result = plainArray.remove(2);

removeAt

removeAt(index: number): T

Removes an element at the specified position from this container.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let result = plainArray.removeAt(1);

removeRangeFrom

removeRangeFrom(index: number, size: number): number

Removes elements in a specified range from this container.

System capability: SystemCapability.Utils.Lang

Parameters

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let result = plainArray.removeRangeFrom(1, 3);

setValueAt

setValueAt(index: number, value: T): void

Sets a value for an element at the specified position in this container.

System capability: SystemCapability.Utils.Lang

Parameters

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string|number> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
plainArray.setValueAt(1, 3546);

toString

toString(): String

Obtains a string that contains all elements in this container.

System capability: SystemCapability.Utils.Lang

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
let result = plainArray.toString();

clear

clear(): void

Clears this container and sets its length to 0.

System capability: SystemCapability.Utils.Lang

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
plainArray.clear();

forEach

forEach(callbackFn: (value: T, index?: number, PlainArray?: PlainArray<T>) => void, thisArg?: Object): void

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

System capability: SystemCapability.Utils.Lang

Parameters

callbackFn |Name|Type|Mandatory|Description| |——–|——–|——–|——–| |value|T|Yes|Value of the element that is currently traversed.| |index|number|No|Position index of the element that is currently traversed. The default value is 0.| |PlainArray|PlainArray<T>|No|Instance that calls the forEach API. The default value is this instance.|

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");
plainArray.forEach((value: string, index?: number) => {
    console.log("value:" + value, "index:" + index);
});

[Symbol.iterator]

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

Obtains an iterator object that contains key-value pairs, where the key is of the number type.

System capability: SystemCapability.Utils.Lang

Return value

Error codes

For details about the error codes, see Utils Error Codes.

Example

let plainArray: PlainArray<string> = new PlainArray();
plainArray.add(1, "squirrel");
plainArray.add(2, "sparrow");

let iter = plainArray[Symbol.iterator]();
let temp: IteratorResult<Object[]> = iter.next();
while(!temp.done) {
  console.log("key:" + temp.value[0]);
  console.log("value:" + temp.value[1]);
  temp = iter.next();
}

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