@stdlib/array/base/flatten3d/README.md

Arrays.

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# flatten3d

> Flatten a three-dimensional nested array.

<section class="usage">

## Usage

```javascript
var flatten3d = require( '@stdlib/array/base/flatten3d' );
```

#### flatten3d( x, shape, colexicographic )

Flattens a three-dimensional nested array.

```javascript
var x = [ [ [ 1, 2 ] ], [ [ 3, 4 ] ] ];

var out = flatten3d( x, [ 2, 1, 2 ], false );
// returns [ 1, 2, 3, 4 ]
```

To flatten in colexicographic order, provide a third argument equal to `true`.

```javascript
var x = [ [ [ 1, 2 ] ], [ [ 3, 4 ] ] ];

var out = flatten3d( x, [ 2, 1, 2 ], true );
// returns [ 1, 3, 2, 4 ]
```

#### flatten3d.assign( x, shape, colexicographic, out, stride, offset )

Flattens a three-dimensional nested array and assigns elements to a provided output array.

```javascript
var Float64Array = require( '@stdlib/array/float64' );

var x = [ [ [ 1, 2 ] ], [ [ 3, 4 ] ] ];
var out = new Float64Array( 4 );

var y = flatten3d.assign( x, [ 2, 1, 2 ], false, out, 1, 0 );
// returns <Float64Array>[ 1, 2, 3, 4 ]

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

y = flatten3d.assign( x, [ 2, 1, 2 ], true, out, 1, 0 );
// returns <Float64Array>[ 1, 3, 2, 4 ]
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   Both functions assume that all nested arrays have the same length (i.e., the input array is **not** a ragged array).

</section>

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<section class="examples">

## Examples

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

```javascript
var flatten3d = require( '@stdlib/array/base/flatten3d' );

var x = [
    [ [ 1, 2 ], [ 3, 4 ] ],
    [ [ 5, 6 ], [ 7, 8 ] ],
    [ [ 9, 10 ], [ 11, 12 ] ],
    [ [ 13, 14 ], [ 15, 16 ] ]
];

var out = flatten3d( x, [ 0, 0, 0 ], false );
// returns []

out = flatten3d( x, [ 0, 0, 0 ], true );
// returns []

out = flatten3d( x, [ 1, 1, 1 ], false );
// returns [ 1 ]

out = flatten3d( x, [ 1, 1, 1 ], true );
// returns [ 1 ]

out = flatten3d( x, [ 2, 2, 2 ], false );
// returns [ 1, 2, 3, 4, 5, 6, 7, 8 ]

out = flatten3d( x, [ 2, 2, 2 ], true );
// returns [ 1, 5, 3, 7, 2, 6, 4, 8 ]

out = flatten3d( x, [ 3, 2, 2 ], false );
// returns [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ]

out = flatten3d( x, [ 3, 2, 2 ], true );
// returns [ 1, 5, 9, 3, 7, 11, 2, 6, 10, 4, 8, 12 ]

out = flatten3d( x, [ 4, 2, 2 ], false );
// returns [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 ]

out = flatten3d( x, [ 4, 2, 2 ], true );
// returns [ 1, 5, 9, 13, 3, 7, 11, 15, 2, 6, 10, 14, 4, 8, 12, 16 ]
```

</section>

<!-- /.examples -->

<!-- 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/array/base/flatten3d-by`][@stdlib/array/base/flatten3d-by]</span><span class="delimiter">: </span><span class="description">flatten a three-dimensional nested array according to a callback function.</span>

</section>

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<section class="links">

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

[@stdlib/array/base/flatten3d-by]: https://github.com/stdlib-js/array/tree/main/base/flatten3d-by

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

</section>

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