@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

Name	Type	Readable	Writable	Description
length	number	Yes	No	Number of elements in a plain array (called container later).

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.

ID	Error Message
10200012	The PlainArray's constructor cannot be directly invoked.

Example

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

isEmpty

isEmpty(): boolean

Checks whether this container is empty.

System capability: SystemCapability.Utils.Lang

Return value

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

Error codes

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

ID	Error Message
10200011	The isEmpty method cannot be bound.

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

Name	Type	Mandatory	Description
key	number	Yes	Target key.

Return value

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

Error codes

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

ID	Error Message
10200011	The has method cannot be bound.

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

Name	Type	Mandatory	Description
key	number	Yes	Target key.

Return value

Type	Description
T	Value of the key.

Error codes

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

ID	Error Message
10200011	The get method cannot be bound.

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

Name	Type	Mandatory	Description
key	number	Yes	Target key.

Return value

Type	Description
number	Returns the position index if obtained; returns -1 otherwise.

Error codes

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

ID	Error Message
10200011	The getIndexOfKey method cannot be bound.

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

Name	Type	Mandatory	Description
value	T	Yes	Value of the target element.

Return value

Type	Description
number	Returns the position index if obtained; returns -1 otherwise.

Error codes

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

ID	Error Message
10200011	The getIndexOfValue method cannot be bound.

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

Name	Type	Mandatory	Description
index	number	Yes	Position index of the target element.

Return value

Type	Description
number	Returns the key of the element if obtained; returns -1 otherwise.

Error codes

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

ID	Error Message
10200011	The getKeyAt method cannot be bound.

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

Name	Type	Mandatory	Description
index	number	Yes	Position index of the target element.

Return value

Type	Description
T	Returns the value of the element if obtained; returns undefined otherwise.

Error codes

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

ID	Error Message
10200011	The getValueAt method cannot be bound.
10200001	The value of index is out of range.

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

Type	Description
PlainArray<T>	New PlainArray instance obtained.

Error codes

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

ID	Error Message
10200011	The clone method cannot be bound.

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

Name	Type	Mandatory	Description
key	number	Yes	Key of the target element.
value	T	Yes	Value of the target element.

Error codes

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

ID	Error Message
10200011	The add method cannot be bound.

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

Name	Type	Mandatory	Description
key	number	Yes	Target key.

Return value

Type	Description
T	Value of the element removed.

Error codes

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

ID	Error Message
10200011	The remove method cannot be bound.

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

Name	Type	Mandatory	Description
index	number	Yes	Position index of the target element.

Return value

Type	Description
T	Element removed.

Error codes

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

ID	Error Message
10200011	The removeAt method cannot be bound.

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

Name	Type	Mandatory	Description
index	number	Yes	Start position of the elements to remove.
size	number	Yes	Number of elements to remove.

Return value

Type	Description
number	Number of elements removed.

Error codes

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

ID	Error Message
10200011	The removeRangeFrom method cannot be bound.
10200001	The value of index is out of range.

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

Name	Type	Mandatory	Description
index	number	Yes	Position index of the target element.
value	T	Yes	Value of the target element.

Error codes

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

ID	Error Message
10200011	The setValueAt method cannot be bound.
10200001	The value of index is out of range.

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

Type	Description
String	String obtained.

Error codes

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

ID	Error Message
10200011	The toString method cannot be bound.

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.

ID	Error Message
10200011	The clear method cannot be bound.

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

Name	Type	Mandatory	Description
callbackFn	function	Yes	Callback invoked to traverse the elements in the container.
thisArg	Object	No	Value of this to use when callbackFn is invoked. The default value is this instance.

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.

ID	Error Message
10200011	The forEach method cannot be bound.

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

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

Error codes

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

ID	Error Message
10200011	The Symbol.iterator method cannot be bound.

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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@ohos.util.PlainArray (Nonlinear Container PlainArray)

Modules to Import

PlainArray

Attributes

constructor

isEmpty

has

get

getIndexOfKey

getIndexOfValue

getKeyAt

getValueAt

clone

add

remove

removeAt

removeRangeFrom

setValueAt

toString

clear

forEach

[Symbol.iterator]

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@ohos.util.PlainArray (Nonlinear Container PlainArray)

Modules to Import

PlainArray

Attributes

constructor

isEmpty

has

get

getIndexOfKey

getIndexOfValue

getKeyAt

getValueAt

clone

add

remove

removeAt

removeRangeFrom

setValueAt

toString

clear

forEach

[Symbol.iterator]

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