@stdlib/array/put/README.md

Arrays.

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# put

> Replace specified elements of an array with provided values.

<section class="usage">

## Usage

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

#### put( x, indices, values\[, options] )

Replaces specified elements of an array with provided values.

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

var out = put( x, [ 1, 3 ], [ 20, 40 ] );
// returns [ 1, 20, 3, 40 ]

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

The function supports the following parameters:

-   **x**: input array.
-   **indices**: list of indices.
-   **values**: values to set. When `indices` contains one or more elements, `values` must be broadcast [compatible][@stdlib/ndarray/base/broadcast-shapes] with `indices` (i.e., must have either one element or the same number of elements as `indices`).
-   **options**: function options.

The function supports the following options:

-   **mode**: index [mode][@stdlib/ndarray/base/ind]. Default: `'normalize'`.

If `indices` is an empty array, the function returns the input array unchanged.

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

var out = put( x, [], [ 20, 40 ] );
// returns [ 1, 2, 3, 4 ]
```

The function supports broadcasting a `values` array containing a single element against an `indices` array containing one or more elements.

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

var out = put( x, [ 1, 3 ], [ 20 ] );
// returns [ 1, 20, 3, 20 ]
```

By default, the function normalizes negative integer indices to positive integer index equivalents.

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

var out = put( x, [ -3, -1 ], [ 20, 40 ] );
// returns [ 1, 20, 3, 40 ]
```

To specify an alternative index [mode][@stdlib/ndarray/base/ind], provide a `mode` option.

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

var out = put( x, [ -10, 10 ], [ 20, 40 ], {
    'mode': 'clamp'
});
// returns [ 20, 2, 3, 40 ]
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   The function mutates the input array `x`.
-   Because each index is only validated at the time of replacing a particular element, mutation may occur even when one or more indices are out-of-bounds, including when the index [mode][@stdlib/ndarray/base/ind] indicates to raise an exception.
-   The `values` array must have a [data type][@stdlib/array/dtypes] which can be [safely cast][@stdlib/array/safe-casts] to the input array data type. Floating-point data types (both real and complex) are allowed to downcast to a lower precision data type of the [same kind][@stdlib/array/same-kind-casts] (e.g., element values from a `'float64'` values array can be assigned to corresponding elements in a `'float32'` input array).

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

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

// Generate a linearly spaced array:
var x = linspace( 0, 100, 11 );
console.log( x );

// Generate an array of random indices:
var N = discreteUniform( 5, 15 );
var indices = filledBy( N, discreteUniform.factory( 0, x.length-1 ) );
console.log( indices );

// Generate an array of random values:
var values = filledBy( N, discreteUniform.factory( 1000, 2000 ) );
console.log( values );

// Update a random sample of elements in `x`:
var out = put( x, indices, values );
console.log( out );
```

</section>

<!-- /.examples -->

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

<section class="related">

</section>

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<section class="links">

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

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

[@stdlib/array/dtypes]: https://github.com/stdlib-js/array/tree/main/dtypes

[@stdlib/array/safe-casts]: https://github.com/stdlib-js/array/tree/main/safe-casts

[@stdlib/array/same-kind-casts]: https://github.com/stdlib-js/array/tree/main/same-kind-casts

</section>

<!-- /.links -->