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emptyLike

Create an uninitialized array having the same length and data type as a provided array.

Usage

To use in Observable,

emptyLike = require( 'https://cdn.jsdelivr.net/gh/stdlib-js/array-empty-like@umd/browser.js' )

To vendor stdlib functionality and avoid installing dependency trees for Node.js, you can use the UMD server build:

var emptyLike = require( 'path/to/vendor/umd/array-empty-like/index.js' )

To include the bundle in a webpage,

<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-empty-like@umd/browser.js"></script>

If no recognized module system is present, access bundle contents via the global scope:

<script type="text/javascript">
(function () {
    window.emptyLike;
})();
</script>

emptyLike( x[, dtype] )

Creates an uninitialized array having the same length and data type as a provided array x.

var x = [ 1, 2, 3, 4, 5 ];

var arr = emptyLike( x );
// returns [ 0, 0, 0, 0, 0 ];

By default, the output array data type is inferred from the provided array x. To return an array having a different data type, provide a dtype argument.

var x = [ 1, 1 ];

var arr = emptyLike( x, 'int32' );
// returns <Int32Array>

Notes

In browser environments, the function always returns zero-filled arrays.
If dtype is 'generic', the function always returns a zero-filled array.
In Node.js versions >=3.0.0, the underlying memory of returned typed arrays is not initialized. Memory contents are unknown and may contain sensitive data.

Examples

<!DOCTYPE html>
<html lang="en">
<body>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-dtypes@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-zeros@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-empty-like@umd/browser.js"></script>
<script type="text/javascript">
(function () {

// Create a zero-filled array:
var x = zeros( 4, 'complex128' );

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

// Generate empty arrays...
var arr;
var i;
for ( i = 0; i < dt.length; i++ ) {
    arr = emptyLike( x, dt[ i ] );
    console.log( arr );
}

})();
</script>
</body>
</html>

See Also

@stdlib/array-empty: create an uninitialized array having a specified length.
@stdlib/array-full-like: create a filled array having the same length and data type as a provided array.
@stdlib/array-ones-like: create an array filled with ones and having the same length and data type as a provided array.
@stdlib/array-zeros-like: create a zero-filled array having the same length and data type as a provided array.
@stdlib/ndarray-empty-like: create an uninitialized ndarray having the same shape and data type as a provided ndarray.

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 © 2016-2025. The Stdlib Authors.