https://github.com/stdlib-js/ndarray-iter-indices
Create an iterator which returns indices for use indexing into an ndarray having a specified shape.
https://github.com/stdlib-js/ndarray-iter-indices
index indices iter iterate iteration iterator javascript matrix multidimensional ndarray node node-js nodejs stdlib subscripts tensor util utilities utility utils
Last synced: 3 months ago
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Create an iterator which returns indices for use indexing into an ndarray having a specified shape.
- Host: GitHub
- URL: https://github.com/stdlib-js/ndarray-iter-indices
- Owner: stdlib-js
- License: apache-2.0
- Created: 2023-10-04T06:43:53.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2026-01-31T03:53:16.000Z (3 months ago)
- Last Synced: 2026-01-31T18:30:30.953Z (3 months ago)
- Topics: index, indices, iter, iterate, iteration, iterator, javascript, matrix, multidimensional, ndarray, node, node-js, nodejs, stdlib, subscripts, tensor, util, utilities, utility, utils
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 581 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
- Notice: NOTICE
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README
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# nditerIndices
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Create an iterator which returns indices for use indexing into an [`ndarray`][@stdlib/ndarray/ctor] having a specified shape.
## Installation
```bash
npm install @stdlib/ndarray-iter-indices
```
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 nditerIndices = require( '@stdlib/ndarray-iter-indices' );
```
#### nditerIndices( shape\[, options] )
Returns an iterator which returns indices for use indexing into an [`ndarray`][@stdlib/ndarray/ctor] having a specified `shape`.
```javascript
var array = require( '@stdlib/ndarray-array' );
var x = array( [ [ [ 1, 2 ], [ 3, 4 ] ], [ [ 5, 6 ], [ 7, 8 ] ] ] );
// returns
var iter = nditerIndices( x.shape );
var v = iter.next().value;
// returns [ 0, 0, 0 ]
v = iter.next().value;
// returns [ 0, 0, 1 ]
v = iter.next().value;
// returns [ 0, 1, 0 ]
// ...
```
The function accepts the following `options`:
- **order**: index iteration order. By default, the returned [iterator][mdn-iterator-protocol] iterates over the last dimensions first, thus corresponding to iteration over contiguous data stored in row-major order. Must be either `'row-major'` or `'column-major'`.
By default, the iterator returns indices such that the last dimensions are iterated over first. To return indices 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 = nditerIndices( x.shape, {
'order': 'column-major'
});
var v = iter.next().value;
// returns [ 0, 0, 0 ]
v = iter.next().value;
// returns [ 1, 0, 0 ]
v = iter.next().value;
// returns [ 0, 1, 0 ]
// ...
```
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.
## Examples
```javascript
var array = require( '@stdlib/ndarray-array' );
var zeroTo = require( '@stdlib/array-base-zero-to' );
var nditerIndices = require( '@stdlib/ndarray-iter-indices' );
// Define an input array:
var x = array( zeroTo( 27 ), {
'shape': [ 3, 3, 3 ]
});
// Create an iterator for generating indices:
var it = nditerIndices( x.shape );
// Perform manual iteration...
var v;
while ( true ) {
v = it.next();
if ( v.done ) {
break;
}
console.log( x.get.apply( x, 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/values`][@stdlib/ndarray/iter/values]: create an iterator which returns individual elements from a provided ndarray.
* * *
## 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 © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/ndarray-iter-indices.svg
[npm-url]: https://npmjs.org/package/@stdlib/ndarray-iter-indices
[test-image]: https://github.com/stdlib-js/ndarray-iter-indices/actions/workflows/test.yml/badge.svg?branch=v0.2.3
[test-url]: https://github.com/stdlib-js/ndarray-iter-indices/actions/workflows/test.yml?query=branch:v0.2.3
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/ndarray-iter-indices/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/ndarray-iter-indices?branch=main
[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg
[chat-url]: https://stdlib.zulipchat.com
[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-indices/tree/deno
[deno-readme]: https://github.com/stdlib-js/ndarray-iter-indices/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/ndarray-iter-indices/tree/umd
[umd-readme]: https://github.com/stdlib-js/ndarray-iter-indices/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/ndarray-iter-indices/tree/esm
[esm-readme]: https://github.com/stdlib-js/ndarray-iter-indices/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/ndarray-iter-indices/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/ndarray-iter-indices/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/values]: https://github.com/stdlib-js/ndarray-iter-values