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# take3d

> Take elements from a three-dimensional nested array.

<section class="usage">

## Usage

```javascript
var take3d = require( '@stdlib/array/base/take3d' );
```

#### take3d( x, indices, dimension, mode )

Takes elements along a specified `dimension` from a three-dimensional nested array according to a specified [index `mode`][@stdlib/ndarray/index-modes].

```javascript
var x = [ [ [ 1, 2 ], [ 3, 4 ] ] ];
var indices = [ 1, 1, 0, 0, -1, -1 ];

var y = take3d( x, indices, 2, 'normalize' );
// returns [ [ [ 2, 2, 1, 1, 2, 2 ], [ 4, 4, 3, 3, 4, 4 ] ] ]
```

The function accepts the following arguments:

-   **x**: input nested array.
-   **indices**: list of indices.
-   **dimension**: dimension along which to take elements. If provided a negative integer, the dimension is resolved relative to the last dimension, with the last dimension being `-1`.
-   **mode**: [index mode][@stdlib/ndarray/index-modes] specifying how to handle an index which is out-of-bounds.

If `indices` is an empty array, the function returns empty arrays along the specified `dimension`.

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

var y = take3d( x, [], 0, 'throw' );
// returns []

var z = take3d( x, [], 1, 'throw' );
// returns [ [] ]

var w = take3d( x, [], 2, 'throw' );
// returns [ [ [], [] ] ]
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   The function does **not** deep copy nested array elements.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var filled3dBy = require( '@stdlib/array/base/filled3d-by' );
var filledBy = require( '@stdlib/array/base/filled-by' );
var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
var take3d = require( '@stdlib/array/base/take3d' );

// Generate a random array:
var shape = [ 3, 3, 3 ];
var x = filled3dBy( shape, discreteUniform.factory( 0, 100 ) );
console.log( x );

// Generate an array of random indices:
var N = discreteUniform( 1, 5 );
var indices = filledBy( N, discreteUniform.factory( 0, shape[2]-1 ) );
console.log( indices );

// Take a random sample of elements from `x`:
var y = take3d( x, indices, 2, 'throw' );
console.log( y );
```

</section>

<!-- /.examples -->

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

<section class="related">

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="links">

[@stdlib/ndarray/index-modes]: https://github.com/stdlib-js/ndarray-index-modes

</section>

<!-- /.links -->
