Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/stdlib-js/ndarray-iter-values

Create an iterator which returns individual elements from a provided ndarray.
https://github.com/stdlib-js/ndarray-iter-values

entries index indices iter iterate iteration iterator javascript matrix multidimensional ndarray node node-js nodejs stdlib tensor util utilities utility utils

Last synced: 10 days ago
JSON representation

Create an iterator which returns individual elements from a provided ndarray.

Awesome Lists containing this project

README 

        



  

    About stdlib...

  

  
We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.


  
The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.


  
When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.


  
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!



# nditerValues



[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] 



> Create an iterator which returns individual elements from a provided [`ndarray`][@stdlib/ndarray/ctor].



## Installation



```bash

npm install @stdlib/ndarray-iter-values

```



Alternatively,



-   To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).

-   If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).

-   For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).



The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.



To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.



## Usage



```javascript

var nditerValues = require( '@stdlib/ndarray-iter-values' );

```



#### nditerValues( x\[, options] )



Returns an iterator which returns individual elements from a provided [`ndarray`][@stdlib/ndarray/ctor].



```javascript

var array = require( '@stdlib/ndarray-array' );



var x = array( [ [ [ 1, 2 ], [ 3, 4 ] ], [ [ 5, 6 ], [ 7, 8 ] ] ] );

// returns 



var iter = nditerValues( x );



var v = iter.next().value;

// returns 1



v = iter.next().value;

// returns 2



v = iter.next().value;

// returns 3



// ...

```



The function accepts the following `options`:



-   **order**: index iteration order. By default, the returned [iterator][mdn-iterator-protocol] returns values according to the layout order of the provided array. Accordingly, for row-major input arrays, the last dimension indices increment fastest. For column-major input arrays, the first dimension indices increment fastest. To override the inferred order and ensure that indices increment in a specific manor, regardless of the input array's layout order, explicitly set the iteration order. Note, however, that iterating according to an order which does not match that of the input array may, in some circumstances, result in performance degradation due to cache misses. Must be either `'row-major'` or `'column-major'`.



By default, the iterator iterates according to the layout order of the input [`ndarray`][@stdlib/ndarray/ctor]. To iterate according to a specified order, set the `order` option.



```javascript

var array = require( '@stdlib/ndarray-array' );



var x = array( [ [ [ 1, 2 ], [ 3, 4 ] ], [ [ 5, 6 ], [ 7, 8 ] ] ], {

    'order': 'row-major'

});

// returns 



var iter = nditerValues( x, {

    'order': 'column-major'

});



var v = iter.next().value;

// returns 1



v = iter.next().value;

// returns 5



v = iter.next().value;

// returns 3



// ...

```



The returned [iterator][mdn-iterator-protocol] protocol-compliant object has the following properties:



-   **next**: function which returns an [iterator][mdn-iterator-protocol] protocol-compliant object containing the next iterated value (if one exists) assigned to a `value` property and a `done` property having a `boolean` value indicating whether the [iterator][mdn-iterator-protocol] is finished.

-   **return**: function which closes an [iterator][mdn-iterator-protocol] and returns a single (optional) argument in an [iterator][mdn-iterator-protocol] protocol-compliant object.



## Notes



-   If an environment supports `Symbol.iterator`, the returned iterator is iterable.

-   A returned iterator does **not** copy a provided [`ndarray`][@stdlib/ndarray/ctor]. To ensure iterable reproducibility, copy the input [`ndarray`][@stdlib/ndarray/ctor] **before** creating an iterator. Otherwise, any changes to the contents of input [`ndarray`][@stdlib/ndarray/ctor] will be reflected in the returned iterator.

-   In environments supporting `Symbol.iterator`, the function **explicitly** does **not** invoke an ndarray's `@@iterator` method, regardless of whether this method is defined.



## Examples



```javascript

var array = require( '@stdlib/ndarray-array' );

var zeroTo = require( '@stdlib/array-base-zero-to' );

var nditerValues = require( '@stdlib/ndarray-iter-values' );



// Define an input array:

var x = array( zeroTo( 27 ), {

    'shape': [ 3, 3, 3 ]

});



// Create an iterator for returning individual elements:

var it = nditerValues( x );



// Perform manual iteration...

var v;

while ( true ) {

    v = it.next();

    if ( v.done ) {

        break;

    }

    console.log( v.value );

}

```



* * *



## See Also



-   [`@stdlib/ndarray-ctor`][@stdlib/ndarray/ctor]: multidimensional array constructor.

-   [`@stdlib/ndarray-iter/entries`][@stdlib/ndarray/iter/entries]: create an iterator which returns \[index, value] pairs for each element in a provided ndarray.

-   [`@stdlib/ndarray-iter/indices`][@stdlib/ndarray/iter/indices]: create an iterator which returns indices for use indexing into an ndarray having a specified shape.



* * *



## Notice



This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.



For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].



#### Community



[![Chat][chat-image]][chat-url]



---



## License



See [LICENSE][stdlib-license].



## Copyright



Copyright © 2016-2024. The Stdlib [Authors][stdlib-authors].



[npm-image]: http://img.shields.io/npm/v/@stdlib/ndarray-iter-values.svg

[npm-url]: https://npmjs.org/package/@stdlib/ndarray-iter-values



[test-image]: https://github.com/stdlib-js/ndarray-iter-values/actions/workflows/test.yml/badge.svg?branch=main

[test-url]: https://github.com/stdlib-js/ndarray-iter-values/actions/workflows/test.yml?query=branch:main



[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/ndarray-iter-values/main.svg

[coverage-url]: https://codecov.io/github/stdlib-js/ndarray-iter-values?branch=main



[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg

[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im



[stdlib]: https://github.com/stdlib-js/stdlib



[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors



[umd]: https://github.com/umdjs/umd

[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules



[deno-url]: https://github.com/stdlib-js/ndarray-iter-values/tree/deno

[deno-readme]: https://github.com/stdlib-js/ndarray-iter-values/blob/deno/README.md

[umd-url]: https://github.com/stdlib-js/ndarray-iter-values/tree/umd

[umd-readme]: https://github.com/stdlib-js/ndarray-iter-values/blob/umd/README.md

[esm-url]: https://github.com/stdlib-js/ndarray-iter-values/tree/esm

[esm-readme]: https://github.com/stdlib-js/ndarray-iter-values/blob/esm/README.md

[branches-url]: https://github.com/stdlib-js/ndarray-iter-values/blob/main/branches.md



[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/ndarray-iter-values/main/LICENSE



[mdn-iterator-protocol]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#The_iterator_protocol



[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/ndarray-ctor



[@stdlib/ndarray/iter/entries]: https://github.com/stdlib-js/ndarray-iter-entries



[@stdlib/ndarray/iter/indices]: https://github.com/stdlib-js/ndarray-iter-indices