npm package: @stdlib/ndarray-iter-interleave-subarrays
Description: Create an iterator which iterates over interleaved subarrays.
Author: The Stdlib Authors
Latest version: 0.1.1

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# nditerInterleaveSubarrays

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> Create an iterator which iterates over interleaved subarrays.

<!-- 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-interleave-subarrays
```

</section>

<section class="usage">

## Usage

```javascript
var nditerInterleaveSubarrays = require( '@stdlib/ndarray-iter-interleave-subarrays' );
```

#### nditerInterleaveSubarrays( arr, ndims )

Returns an iterator which iterates over interleaved subarrays.

```javascript
var array = require( '@stdlib/ndarray-array' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );

var x = array( [ [ [ 1, 2 ], [ 3, 4 ] ], [ [ 5, 6 ], [ 7, 8 ] ] ] );
// returns <ndarray>

var iter = nditerInterleaveSubarrays( [ x, x ], 2 );

var v = iter.next().value;
// returns <ndarray>

var arr = ndarray2array( v );
// returns [ [ 1, 2 ], [ 3, 4 ] ]

v = iter.next().value;
// returns <ndarray>

arr = ndarray2array( v );
// returns [ [ 1, 2 ], [ 3, 4 ] ]

// ...
```

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

-   All provided [`ndarrays`][@stdlib/ndarray/ctor] must be [broadcast compatible][@stdlib/ndarray/base/broadcast-shapes].
-   After broadcasting, each broadcasted input [`ndarray`][@stdlib/ndarray/ctor] must have at least `ndims+1` dimensions.
-   For input [`ndarrays`][@stdlib/ndarray/ctor] supporting read-only views, the function returns **read-only** views of interleaved subarrays. As input [`ndarrays`][@stdlib/ndarray/ctor] may be broadcasted, a view is typically **not** contiguous. As more than one element of a returned view may refer to the same memory location, writing to a view may affect multiple elements. If you need to write to a subarray, copy the subarray **before** attempting mutation.
-   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.

</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 ndarray2array = require( '@stdlib/ndarray-to-array' );
var nditerInterleaveSubarrays = require( '@stdlib/ndarray-iter-interleave-subarrays' );

// Define input arrays:
var x = array( zeroTo( 27 ), {
    'shape': [ 3, 3, 3 ]
});
var y = array( zeroTo( 9 ), {
    'shape': [ 3, 3 ]
});

// Create an iterator for iterating over interleaved matrices:
var it = nditerInterleaveSubarrays( [ x, y ], 2 );

// Perform manual iteration...
var v;
while ( true ) {
    v = it.next();
    if ( v.done ) {
        break;
    }
    console.log( ndarray2array( v.value ) );
}
```

</section>

<!-- /.examples -->

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<section class="references">

</section>

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<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/ndarray-iter/subarrays`][@stdlib/ndarray/iter/subarrays]</span><span class="delimiter">: </span><span class="description">create an iterator which iterates over each subarray in a stack of subarrays.</span>
-   <span class="package-name">[`@stdlib/ndarray-slice`][@stdlib/ndarray/slice]</span><span class="delimiter">: </span><span class="description">return a read-only view of an input 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].

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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

[@stdlib/ndarray/base/broadcast-shapes]: https://www.npmjs.com/package/@stdlib/ndarray-base-broadcast-shapes

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