sliceFrom

Return a shifted view of an input ndarray.

Usage

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 of null or undefined indicates 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 writable parameter 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 ] ] ]