About stdlib...
We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.
The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.
When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
sliceFrom
Return a shifted view of an input ndarray.
Installation
npm install @stdlib/ndarray-base-slice-fromUsage
var sliceFrom = require( '@stdlib/ndarray-base-slice-from' );sliceFrom( x, start, strict, writable )
Returns a shifted view of an input ndarray.
var ndarray = require( '@stdlib/ndarray-ctor' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var buffer = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
var shape = [ 3, 2 ];
var strides = [ 2, 1 ];
var offset = 0;
var x = ndarray( 'generic', buffer, shape, strides, offset, 'row-major' );
// returns <ndarray>
var sh = x.shape;
// returns [ 3, 2 ]
var arr = ndarray2array( x );
// returns [ [ 1.0, 2.0 ], [ 3.0, 4.0 ], [ 5.0, 6.0 ] ]
var s = [ 1, null ];
var y = sliceFrom( x, s, false, false );
// returns <ndarray>
sh = y.shape;
// returns [ 2, 2 ]
arr = ndarray2array( y );
// returns [ [ 3.0, 4.0 ], [ 5.0, 6.0 ] ]The function accepts the following arguments:
- x: input ndarray.
-
start: an array of starting indices (inclusive). Each element must be either
null,undefined, or an integer. A value ofnullorundefinedindicates to include all elements along a corresponding dimension. A negative integer indicates to resolve a starting index relative to the last element along a corresponding dimension, with the last element having index-1. - strict: boolean indicating whether to enforce strict bounds checking.
- writable: boolean indicating whether a returned ndarray should be writable.
Notes
- The
writableparameter only applies to ndarray constructors supporting read-only instances.
Examples
var array = require( '@stdlib/ndarray-array' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var zeroTo = require( '@stdlib/array-base-zero-to' );
var sliceFrom = require( '@stdlib/ndarray-base-slice-from' );
// Create a linear ndarray buffer:
var buf = zeroTo( 27 );
// Create an ndarray:
var x = array( buf, {
'shape': [ 3, 3, 3 ]
});
// Get the last two rows of each matrix:
var y1 = sliceFrom( x, [ null, 1, null ], false, false );
// returns <ndarray>
var a1 = ndarray2array( y1 );
// returns [ [ [ 3, 4, 5 ], [ 6, 7, 8 ] ], [ [ 12, 13, 14 ], [ 15, 16, 17 ] ], [ [ 21, 22, 23 ], [ 24, 25, 26 ] ] ]
// Get the last two rows and columns of each matrix:
var y2 = sliceFrom( x, [ null, 1, 1 ], false, false );
// returns <ndarray>
var a2 = ndarray2array( y2 );
// returns [ [ [ 4, 5 ], [ 7, 8 ] ], [ [ 13, 14 ], [ 16, 17 ] ], [ [ 22, 23 ], [ 25, 26 ] ] ]
// Get the last two 2x2 matrices:
var y3 = sliceFrom( x, [ 1, 1, 1 ], false, false );
// returns <ndarray>
var a3 = ndarray2array( y3 );
// returns [ [ [ 13, 14 ], [ 16, 17 ] ], [ [ 22, 23 ], [ 25, 26 ] ] ]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 © 2016-2024. The Stdlib Authors.