@stdlib/array-empty-like NPM

emptyLike

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

Installation

npm install @stdlib/array-empty-like

Usage

var emptyLike = require( '@stdlib/array-empty-like' );

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 ];

The function recognizes the following data types:

float64: double-precision floating-point numbers (IEEE 754)
float32: single-precision floating-point numbers (IEEE 754)
complex128: double-precision complex floating-point numbers
complex64: single-precision complex floating-point numbers
int32: 32-bit two's complement signed integers
uint32: 32-bit unsigned integers
int16: 16-bit two's complement signed integers
uint16: 16-bit unsigned integers
int8: 8-bit two's complement signed integers
uint8: 8-bit unsigned integers
uint8c: 8-bit unsigned integers clamped to 0-255
generic: generic JavaScript values

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

var dtypes = require( '@stdlib/array-dtypes' );
var zeros = require( '@stdlib/array-zeros' );
var emptyLike = require( '@stdlib/array-empty-like' );

// 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 );
}

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.