npm install @stdlib/blas-ext-join

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
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• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

var join = require( '@stdlib/blas-ext-join' );

Returns an ndarray created by joining elements using a separator along one or more ndarray dimensions.

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

// Create an input ndarray:
var x = array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
// returns <ndarray>

// Perform operation:
var out = join( x );
// returns <ndarray>[ '1,2,3,4,5,6' ]

The function has the following parameters:

• x: input ndarray.
• options: function options (optional).

The function accepts the following options:

• sep: separator. May be either a scalar value or an ndarray having a "generic" data type. If provided an ndarray, the value must have a shape which is broadcast-compatible with the complement of the shape defined by options.dims. For example, given the input shape [2, 3, 4] and options.dims=[0], an ndarray separator value must have a shape which is broadcast-compatible with the shape [3, 4]. Similarly, when performing the operation over all elements in a provided input ndarray, an ndarray separator value must be a zero-dimensional ndarray. Default: ,.
• dims: list of dimensions over which to perform operation. If not provided, the function performs the operation over all elements in a provided input ndarray.
• keepdims: boolean indicating whether the reduced dimensions should be included in the returned ndarray as singleton dimensions. Default: false.

By default, the function joins ndarray elements by using , as a separator. To perform the operation with a different separator, provide a sep option.

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

var x = array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );

var out = join( x, {
    'sep': '|'
});
// returns <ndarray>[ '1|2|3|4|5|6' ]

By default, the function performs the operation over all elements in a provided input ndarray. To perform the operation over specific dimensions, provide a dims option.

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

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

var out = join( x, {
    'dims': [ 0 ]
});
// returns <ndarray>[ '1,3', '2,4' ]

out = join( x, {
    'dims': [ 1 ]
});
// returns <ndarray>[ '1,2', '3,4' ]

out = join( x, {
    'dims': [ 0, 1 ]
});
// returns <ndarray>[ '1,2,3,4' ]

By default, the function excludes reduced dimensions from the output ndarray. To include the reduced dimensions as singleton dimensions, set the keepdims option to true.

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

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

var opts = {
    'dims': [ 0 ],
    'keepdims': true
};

var out = join( x, opts );
// returns <ndarray>[ [ '1,3', '2,4' ] ]

Joins elements of an input ndarray using a separator along one or more ndarray dimensions and assigns results to a provided output ndarray.

var array = require( '@stdlib/ndarray-array' );
var scalar2ndarray = require( '@stdlib/ndarray-from-scalar' );

var x = array( [ 1.0, 2.0, 3.0, 4.0 ] );
var y = scalar2ndarray( '', {
    'dtype': 'generic'
});

var out = join.assign( x, y );
// returns <ndarray>[ '1,2,3,4' ]

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

The method has the following parameters:

• x: input ndarray.
• out: output ndarray.
• options: function options (optional).

The method accepts the following options:

• sep: separator. May be either a scalar value or an ndarray having a "generic" data type. If provided an ndarray, the value must have a shape which is broadcast-compatible with the complement of the shape defined by options.dims. For example, given the input shape [2, 3, 4] and options.dims=[0], an ndarray separator value must have a shape which is broadcast-compatible with the shape [3, 4]. Similarly, when performing the operation over all elements in a provided input ndarray, an ndarray separator value must be a zero-dimensional ndarray. Default: ,.
• dims: list of dimensions over which to perform operation. If not provided, the function performs the operation over all elements in a provided input ndarray.

• Setting the keepdims option to true can be useful when wanting to ensure that the output ndarray is broadcast-compatible with ndarrays having the same shape as the input ndarray.

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.

See LICENSE.

Copyright © 2016-2026. The Stdlib Authors.