@stdlib/array/filled-by/README.md

Arrays.

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# filledarrayBy

> Create a filled array according to a provided callback function.

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## Usage

```javascript
var filledarrayBy = require( '@stdlib/array/filled-by' );
```

#### filledarrayBy( \[dtype] )

Creates a filled array having a specified [data type][@stdlib/array/dtypes] `dtype`.

```javascript
var arr = filledarrayBy();
// returns <Float64Array>
```

By default, the output array [data type][@stdlib/array/dtypes] is `float64` (i.e., a [typed array][mdn-typed-array]). To specify an alternative [data type][@stdlib/array/dtypes], provide a `dtype` argument.

```javascript
var arr = filledarrayBy( 'int32' );
// returns <Int32Array>
```

#### filledarrayBy( length\[, dtype], clbk\[, thisArg] )

Returns a filled array according to a provided callback function and having a specified `length`.

```javascript
function constant() {
    return 1.0;
}

var arr1 = filledarrayBy( 5, constant );
// returns <Float64Array>[ 1.0, 1.0, 1.0, 1.0, 1.0 ]

var arr2 = filledarrayBy( 5, 'uint8', constant );
// returns <Uint8Array>[ 1, 1, 1, 1, 1 ]
```

#### filledarrayBy( array\[, dtype], clbk\[, thisArg] )

Creates a filled array from another array (or array-like object) according to a provided callback function.

```javascript
var arr0 = {
    '0': 0.5,
    '1': 0.5,
    '2': 0.5,
    'length': 3
};

function clbk1() {
    return 1.0;
}
var arr1 = filledarrayBy( arr0, clbk1 );
// returns <Float64Array>[ 1.0, 1.0, 1.0 ]

function clbk2() {
    return 2.0;
}
var arr2 = filledarrayBy( arr1, clbk2 );
// returns <Float64Array>[ 2.0, 2.0, 2.0 ]

function clbk3() {
    return 3.0;
}
var arr3 = filledarrayBy( arr1, 'int32', clbk3 );
// returns <Int32Array>[ 3, 3, 3 ]
```

#### filledarrayBy( iterable\[, dtype], clbk\[, thisArg] )

Creates a filled array from an iterable according to a provided callback function.

```javascript
var iterConstant = require( '@stdlib/iter/constant' );

function clbk() {
    return 1.0;
}

var it = iterConstant( 3.0, {
    'iter': 3
});

var arr1 = filledarrayBy( it, clbk );
// returns <Float64Array>[ 1.0, 1.0, 1.0 ]

var arr2 = filledarrayBy( it, 'float32', clbk );
// returns <Float32Array>[ 1.0, 1.0, 1.0 ]
```

#### filledarrayBy( buffer\[, byteOffset\[, length]]\[, dtype], clbk\[, thisArg] )

Returns a filled [typed array][mdn-typed-array] view of an [`ArrayBuffer`][mdn-arraybuffer] according to a provided callback function.

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

function clbk() {
    return 1.0;
}

var buf = new ArrayBuffer( 32 );
var arr = filledarrayBy( buf, clbk );
// returns <Float64Array>[ 1.0, 1.0, 1.0, 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 'float32', clbk );
// returns <Float32Array>[ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 16, clbk );
// returns <Float64Array>[ 1.0, 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 16, 'float32', clbk );
// returns <Float32Array>[ 1.0, 1.0, 1.0, 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 16, 1, clbk );
// returns <Float64Array>[ 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 10, 4, 'int16', clbk );
// returns <Int16Array>[ 1, 1, 1, 1 ]
```

</section>

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<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

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## Notes

-   Creating a generic [array][mdn-array] from an [`ArrayBuffer`][mdn-arraybuffer] is **not** supported.

-   A callback function is provided a single argument:

    -   **index**: the current array index.

</section>

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## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random/base/discrete-uniform' ).factory;
var dtypes = require( '@stdlib/array/typed-real-dtypes' );
var filledarrayBy = require( '@stdlib/array/filled-by' );

// Create a pseudorandom number generator:
var rand = discreteUniform( 0, 100 );

// Get a list of array data types:
var dt = dtypes();

// Generate filled arrays...
var arr;
var i;
for ( i = 0; i < dt.length; i++ ) {
    arr = filledarrayBy( 10, dt[ i ], rand );
    console.log( arr );
}
```

</section>

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</section>

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* * *

## See Also

-   <span class="package-name">[`@stdlib/array/filled`][@stdlib/array/filled]</span><span class="delimiter">: </span><span class="description">create a filled array.</span>
-   <span class="package-name">[`@stdlib/array/typed`][@stdlib/array/typed]</span><span class="delimiter">: </span><span class="description">create a typed array.</span>

</section>

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[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array

[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

[mdn-arraybuffer]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer

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

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

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

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</section>

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