Create an uninitialized ndarray having the same shape and data type as a provided ndarray.
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> Create an uninitialized [ndarray][@stdlib/ndarray/ctor] having the same shape and [data type][@stdlib/ndarray/dtypes] as a provided ndarray.
``bash`
npm install @stdlib/ndarray-empty-like
`javascript`
var emptyLike = require( '@stdlib/ndarray-empty-like' );
#### emptyLike( x\[, options] )
Creates an uninitialized [ndarray][@stdlib/ndarray/ctor] having the same shape and [data type][@stdlib/ndarray/dtypes] as a provided ndarray.
`javascript
var getShape = require( '@stdlib/ndarray-shape' );
var getDType = require( '@stdlib/ndarray-dtype' );
var zeros = require( '@stdlib/ndarray-zeros' );
var x = zeros( [ 2, 2 ] );
// returns
var y = emptyLike( x );
// returns
var sh = getShape( y );
// returns [ 2, 2 ]
var dt = String( getDType( y ) );
// returns 'float64'
`
The function supports the following options:
- dtype: output [ndarray][@stdlib/ndarray/ctor] [data type][@stdlib/ndarray/dtypes]. Overrides the input ndarray's inferred [data type][@stdlib/ndarray/dtypes].
- shape: output [ndarray][@stdlib/ndarray/ctor] shape. Overrides the input ndarray's inferred shape.
- order: specifies whether the output [ndarray][@stdlib/ndarray/ctor] should be 'row-major' (C-style) or 'column-major' (Fortran-style). Overrides the input ndarray's inferred order.ndarray
- mode: specifies how to handle indices which exceed array dimensions (see [][@stdlib/ndarray/ctor]). Default: 'throw'.ndarray
- submode: a mode array which specifies for each dimension how to handle subscripts which exceed array dimensions (see [][@stdlib/ndarray/ctor]). If provided fewer modes than dimensions, the constructor recycles modes using modulo arithmetic. Default: [ options.mode ].
To override either the dtype, shape, or order, specify the corresponding option. For example, to override the inferred [data type][@stdlib/ndarray/dtypes],
`javascript
var getShape = require( '@stdlib/ndarray-shape' );
var getDType = require( '@stdlib/ndarray-dtype' );
var zeros = require( '@stdlib/ndarray-zeros' );
var x = zeros( [ 2, 2 ] );
// returns
var dt = String( getDType( x ) );
// returns 'float64'
var y = emptyLike( x, {
'dtype': 'int32'
});
// returns
var sh = getShape( y );
// returns [ 2, 2 ]
dt = String( getDType( y ) );
// returns 'int32'
`
- If the resolved output data type is 'generic', the function always returns a zero-filled array.
- For returned [ndarrays][@stdlib/ndarray/ctor] whose underlying memory is not initialized, memory contents are unknown and may contain sensitive data.
`javascript
var getData = require( '@stdlib/ndarray-data-buffer' );
var dtypes = require( '@stdlib/ndarray-dtypes' );
var empty = require( '@stdlib/ndarray-empty' );
var emptyLike = require( '@stdlib/ndarray-empty-like' );
// Get a list of data types:
var dt = dtypes( 'integer_and_generic' );
// Generate uninitialized arrays...
var x;
var y;
var i;
for ( i = 0; i < dt.length; i++ ) {
x = empty( [ 2, 2 ], {
'dtype': dt[ i ]
});
y = emptyLike( x );
console.log( getData( y ) );
}
`
*
- [@stdlib/ndarray-empty][@stdlib/ndarray/empty]: create an uninitialized ndarray having a specified shape and data type.
- [@stdlib/ndarray-zeros-like][@stdlib/ndarray/zeros-like]: create a zero-filled ndarray having the same shape and data type as a provided ndarray.
*
This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].
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---
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[@stdlib/ndarray/zeros-like]: https://www.npmjs.com/package/@stdlib/ndarray-zeros-like