sliceTo
Return a truncated view of an input ndarray.
Usage
var sliceTo = require( '@stdlib/ndarray/base/slice-to' );
sliceTo( x, stop, strict, writable )
Returns a truncated 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 = [ 2, null ];
var y = sliceTo( x, s, false, false );
// returns <ndarray>
sh = y.shape;
// returns [ 2, 2 ]
arr = ndarray2array( y );
// returns [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ]
The function accepts the following arguments:
- x: input ndarray.
- stop: an array of ending indices (exclusive). Each element must be either
null
,undefined
, or an integer. A value ofnull
orundefined
indicates to include all elements along a corresponding dimension. A negative integer indicates to resolve an ending 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 sliceTo = require( '@stdlib/ndarray/base/slice-to' );
// Create a linear ndarray buffer:
var buf = zeroTo( 27 );
// Create an ndarray:
var x = array( buf, {
'shape': [ 3, 3, 3 ]
});
// Get the first two rows of each matrix:
var y1 = sliceTo( x, [ null, 2, null ], false, false );
// returns <ndarray>
var a1 = ndarray2array( y1 );
// returns [ [ [ 0, 1, 2 ], [ 3, 4, 5 ] ], [ [ 9, 10, 11 ], [ 12, 13, 14 ] ], [ [ 18, 19, 20 ], [ 21, 22, 23 ] ] ]
// Get the first two rows and columns of each matrix:
var y2 = sliceTo( x, [ null, 2, 2 ], false, false );
// returns <ndarray>
var a2 = ndarray2array( y2 );
// returns [ [ [ 0, 1 ], [ 3, 4 ] ], [ [ 9, 10 ], [ 12, 13 ] ], [ [ 18, 19 ], [ 21, 22 ] ] ]
// Get the first two 2x2 matrices:
var y3 = sliceTo( x, [ 2, 2, 2 ], false, false );
// returns <ndarray>
var a3 = ndarray2array( y3 );
// returns [ [ [ 0, 1 ], [ 3, 4 ] ], [ [ 9, 10 ], [ 12, 13 ] ] ]