npm package: @stdlib/ndarray-base-flipud
Description: Return a view of an input ndarray in which the order of elements along the second-to-last dimension is reversed.
Author: The Stdlib Authors
Latest version: 0.2.3

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# flipud

[![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 view of an input ndarray in which the order of elements along the second-to-last dimension is reversed.

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/ndarray-base-flipud
```

</section>

<section class="usage">

## Usage

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

#### flipud( x, writable )

Returns a view of an input ndarray in which the order of elements along the second-to-last dimension is reversed.

```javascript
var ndarray = require( '@stdlib/ndarray-ctor' );
var getShape = require( '@stdlib/ndarray-shape' );

var buffer = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
var shape = [ 3, 2 ];
var strides = [ 2, 1 ];
var offset = 0;

var x = ndarray( 'generic', buffer, shape, strides, offset, 'row-major' );
// returns <ndarray>[ [ 1.0, 2.0 ], [ 3.0, 4.0 ], [ 5.0, 6.0 ] ]

var sh = getShape( x );
// returns [ 3, 2 ]

var y = flipud( x, false );
// returns <ndarray>[ [ 5.0, 6.0 ], [ 3.0, 4.0 ], [ 1.0, 2.0 ] ]

sh = getShape( y );
// returns [ 3, 2 ]
```

The function accepts the following arguments:

-   **x**: input ndarray.
-   **writable**: boolean indicating whether a returned ndarray should be writable.

</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 provided a zero-dimensional ndarray, as the ndarray has no dimensions to reverse, the function simply returns a new view of the input ndarray. Similarly, if provided a one-dimensional ndarray, as the ndarray has only one dimension, the function simply returns a new view of the input ndarray.
-   The `writable` parameter **only** applies to ndarray constructors supporting **read-only** instances.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

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

// Create a linear ndarray buffer:
var buf = zeroTo( 16 );

// Create a three-dimensional ndarray:
var x = array( buf, {
    'shape': [ 2, 4, 2 ]
});

// Reverse the order of second-to-last dimension:
var y = flipud( x, false );
// returns <ndarray>

var arr = ndarray2array( y );
// returns [ [ [ 6, 7 ], [ 4, 5 ], [ 2, 3 ], [ 0, 1 ] ], [ [ 14, 15 ], [ 12, 13 ], [ 10, 11 ], [ 8, 9 ] ] ]
```

</section>

<!-- /.examples -->

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

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