npm package: @stdlib/ndarray-unshift
Description: Return a one-dimensional ndarray formed by prepending provided scalar values to a one-dimensional input ndarray.
Author: The Stdlib Authors
Latest version: 0.1.1

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# unshift

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

> Return a one-dimensional [ndarray][@stdlib/ndarray/ctor] formed by prepending provided scalar values to a one-dimensional input [ndarray][@stdlib/ndarray/ctor].

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/ndarray-unshift
```

</section>

<section class="usage">

## Usage

```javascript
var unshift = require( '@stdlib/ndarray-unshift' );
```

#### unshift( x, ...values )

Returns a one-dimensional [ndarray][@stdlib/ndarray/ctor] formed by prepending provided scalar values to a one-dimensional input [ndarray][@stdlib/ndarray/ctor].

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

var x = array( [ 1.0, 2.0, 3.0, 4.0 ] );

var out = unshift( x, -2.0, -1.0, 0.0 );
// returns <ndarray>[ -2.0, -1.0, 0.0, 1.0, 2.0, 3.0, 4.0 ]
```

The function accepts the following arguments:

-   **x**: input [ndarray][@stdlib/ndarray/ctor]. Must be one-dimensional.
-   **...values**: scalar values to prepend.

#### unshift.assign( x, ...values, out )

Prepends provided scalar values to a one-dimensional input [ndarray][@stdlib/ndarray/ctor] and assigns the result to a provided one-dimensional output [ndarray][@stdlib/ndarray/ctor].

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

var x = array( [ 1.0, 2.0, 3.0, 4.0 ] );
var y = zeros( [ 7 ] );

var out = unshift.assign( x, -2.0, -1.0, 0.0, y );
// returns <ndarray>[ -2.0, -1.0, 0.0, 1.0, 2.0, 3.0, 4.0 ]

var bool = ( out === y );
// returns true
```

The function accepts the following arguments:

-   **x**: input [ndarray][@stdlib/ndarray/ctor]. Must be one-dimensional.
-   **...values**: scalar values to prepend.
-   **out**: output [ndarray][@stdlib/ndarray/ctor]. Must be one-dimensional.

</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

-   Scalar values are cast to the [data type][@stdlib/ndarray/dtypes] of the input [ndarray][@stdlib/ndarray/ctor].

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

```javascript
var discreteUniform = require( '@stdlib/random-discrete-uniform' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var unshift = require( '@stdlib/ndarray-unshift' );

var opts = {
    'dtype': 'generic'
};
var x = discreteUniform( [ 6 ], 0, 10, opts );
console.log( ndarray2array( x ) );

var out = unshift( x, 12, 14 );
console.log( ndarray2array( out ) );
```

</section>

<!-- /.examples -->

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<section class="related">

</section>

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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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[npm-image]: http://img.shields.io/npm/v/@stdlib/ndarray-unshift.svg
[npm-url]: https://npmjs.org/package/@stdlib/ndarray-unshift

[test-image]: https://github.com/stdlib-js/ndarray-unshift/actions/workflows/test.yml/badge.svg?branch=v0.1.1
[test-url]: https://github.com/stdlib-js/ndarray-unshift/actions/workflows/test.yml?query=branch:v0.1.1

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/ndarray-unshift/main.svg
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[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-unshift/tree/deno
[deno-readme]: https://github.com/stdlib-js/ndarray-unshift/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/ndarray-unshift/tree/umd
[umd-readme]: https://github.com/stdlib-js/ndarray-unshift/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/ndarray-unshift/tree/esm
[esm-readme]: https://github.com/stdlib-js/ndarray-unshift/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/ndarray-unshift/blob/main/branches.md

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

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

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

</section>

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