# Unary
> Apply a unary callback to elements in a input ndarray and assign results to elements in an output ndarray.
## Usage
```javascript
var unary = require( '@stdlib/ndarray/base/unary' );
```
#### unary( arrays, fcn )
Applies a unary callback to elements in a input ndarray and assign results to elements in an output ndarray.
```javascript
var Float64Array = require( '@stdlib/array/float64' );
var unary = require( '@stdlib/ndarray/base/unary' );
function scale( x ) {
return x * 10.0;
}
// Create data buffers:
var arr = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ];
var xbuf = new Float64Array( arr);
var ybuf = new Float64Array( 6 );
// Define the shape of the input and output arrays:
var shape = [ 3, 1, 2 ];
// Define the array strides:
var sx = [ 4, 4, 1 ];
var sy = [ 2, 2, 1 ];
// Define the index offsets:
var ox = 1;
var oy = 0;
// Create the input and output ndarray-like objects:
var x = {
'dtype': 'float64',
'data': xbuf,
'shape': shape,
'strides': sx,
'offset': ox,
'order': 'row-major'
};
var y = {
'dtype': 'float64',
'data': ybuf,
'shape': shape,
'strides': sy,
'offset': oy,
'order': 'row-major'
};
// Apply the unary function:
unary( [ x, y ], scale );
console.log( y.data );
// => [ 20.0, 30.0, 60.0, 70.0, 100.0, 110.0 ]
```
## Examples
```javascript
var discreteUniform = require( '@stdlib/random/base/discrete-uniform' ).factory;
var filledarray = require( '@stdlib/array/filled' );
var gfillBy = require( '@stdlib/blas/ext/base/gfill-by' );
var shape2strides = require( '@stdlib/ndarray/base/shape2strides' );
var ndarray2array = require( '@stdlib/ndarray/base/to-array' );
var unary = require( '@stdlib/ndarray/base/unary' );
function scale( x ) {
return x * 10;
}
var N = 10;
var xbuf = filledarray( 0, N, 'generic' );
gfillBy( xbuf.length, xbuf, 1, discreteUniform( -100, 100 ) );
var x = {
'dtype': 'generic',
'data': xbuf,
'shape': [ 5, 2 ],
'strides': [ 2, 1 ],
'offset': 0,
'order': 'row-major'
};
var y = {
'dtype': 'generic',
'data': filledarray( 0, N, 'generic' ),
'shape': x.shape.slice(),
'strides': shape2strides( x.shape, 'column-major' ),
'offset': 0,
'order': 'column-major'
};
unary( [ x, y ], scale );
console.log( ndarray2array( x.data, x.shape, x.strides, x.offset, x.order ) );
console.log( ndarray2array( y.data, y.shape, y.strides, y.offset, y.order ) );
```