unshift

Return a one-dimensional ndarray formed by prepending provided scalar values to a one-dimensional input ndarray.

Installation

npm install @stdlib/ndarray-unshift

Usage

var unshift = require( '@stdlib/ndarray-unshift' );

unshift( x, ...values )

Returns a one-dimensional ndarray formed by prepending provided scalar values to a one-dimensional input ndarray.

var array = require( '@stdlib/ndarray-array' );

var x = array( [ 1.0, 2.0, 3.0, 4.0 ] );

var out = unshift( x, -2.0, -1.0, 0.0 );
// returns <ndarray>[ -2.0, -1.0, 0.0, 1.0, 2.0, 3.0, 4.0 ]

The function accepts the following arguments:

• x: input ndarray. Must be one-dimensional.
• ...values: scalar values to prepend.

unshift.assign( x, ...values, out )

Prepends provided scalar values to a one-dimensional input ndarray and assigns the result to a provided one-dimensional output ndarray.

var array = require( '@stdlib/ndarray-array' );
var zeros = require( '@stdlib/ndarray-zeros' );

var x = array( [ 1.0, 2.0, 3.0, 4.0 ] );
var y = zeros( [ 7 ] );

var out = unshift.assign( x, -2.0, -1.0, 0.0, y );
// returns <ndarray>[ -2.0, -1.0, 0.0, 1.0, 2.0, 3.0, 4.0 ]

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

The function accepts the following arguments:

• x: input ndarray. Must be one-dimensional.
• ...values: scalar values to prepend.
• out: output ndarray. Must be one-dimensional.

Notes

• Scalar values are cast to the data type of the input ndarray.

Examples

var discreteUniform = require( '@stdlib/random-discrete-uniform' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var unshift = require( '@stdlib/ndarray-unshift' );

var opts = {
    'dtype': 'generic'
};
var x = discreteUniform( [ 6 ], 0, 10, opts );
console.log( ndarray2array( x ) );

var out = unshift( x, 12, 14 );
console.log( ndarray2array( out ) );

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.