npm package: @stdlib/ndarray-iter-indices
Description: Create an iterator which returns indices for use indexing into an ndarray having a specified shape.
Author: The Stdlib Authors
Latest version: 0.2.4

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# nditerIndices

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> Create an iterator which returns indices for use indexing into an [`ndarray`][@stdlib/ndarray/ctor] having a specified shape.

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/ndarray-iter-indices
```

</section>

<section class="usage">

## 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 <ndarray>

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 <ndarray>

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.

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

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

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```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 ) );
}
```

</section>

<!-- /.examples -->

<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="references">

</section>

<!-- /.references -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/ndarray-ctor`][@stdlib/ndarray/ctor]</span><span class="delimiter">: </span><span class="description">multidimensional array constructor.</span>
-   <span class="package-name">[`@stdlib/ndarray-iter/entries`][@stdlib/ndarray/iter/entries]</span><span class="delimiter">: </span><span class="description">create an iterator which returns \[index, value] pairs for each element in a provided ndarray.</span>
-   <span class="package-name">[`@stdlib/ndarray-iter/values`][@stdlib/ndarray/iter/values]</span><span class="delimiter">: </span><span class="description">create an iterator which returns individual elements from a provided ndarray.</span>

</section>

<!-- /.related -->

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<section class="main-repo" >

* * *

## 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 &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

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

[@stdlib/ndarray/ctor]: https://www.npmjs.com/package/@stdlib/ndarray-ctor

<!-- <related-links> -->

[@stdlib/ndarray/iter/entries]: https://www.npmjs.com/package/@stdlib/ndarray-iter-entries

[@stdlib/ndarray/iter/values]: https://www.npmjs.com/package/@stdlib/ndarray-iter-values

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