Return a read-only view of an input ndarray when sliced along a specified dimension.
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Return a read-only view of an input
ndarray
when sliced along a specified dimension.
npm install @stdlib/ndarray-slice-dimension
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var sliceDimension = require( '@stdlib/ndarray-slice-dimension' );
Returns a read-only view of an input ndarray
when sliced along a specified dimension.
var Slice = require( '@stdlib/slice-ctor' );
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 = new Slice( null, null, -1 );
// returns <Slice>
var y = sliceDimension( x, 0, s );
// returns <ndarray>
sh = y.shape;
// returns [ 3, 2 ]
arr = ndarray2array( y );
// returns [ [ 5.0, 6.0 ], [ 3.0, 4.0 ], [ 1.0, 2.0 ] ]
The function accepts the following arguments:
ndarray
.-1
.Slice
instance, null
, undefined
, or an integer. If provided null
or undefined
, the argument is equivalent to new Slice()
(i.e., the returned view should include all elements along a specified dimension). If provided an integer less than zero, the corresponding element along the specified dimension is resolved relative to the last element along that dimension. For negative integers, the last element corresponds to the value -1
.The function supports the following options
:
By default, the function throws an error when provided a slice which exceeds array bounds. To return an empty array when a slice exceeds array bounds, set the strict
option to false
.
var Slice = require( '@stdlib/slice-ctor' );
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 = new Slice( 10, 20, 2 );
// returns <Slice>
var y = sliceDimension( x, 1, s, {
'strict': false
});
// returns <ndarray>
sh = y.shape;
// returns [ 3, 0 ]
arr = ndarray2array( y );
// returns []
var S = require( '@stdlib/slice-ctor' );
var array = require( '@stdlib/ndarray-array' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var zeroTo = require( '@stdlib/array-base-zero-to' );
var sliceDimension = require( '@stdlib/ndarray-slice-dimension' );
// Alias `null` to allow for more compact indexing expressions:
var _ = null;
// Create a linear ndarray buffer:
var buf = zeroTo( 27 );
// Create an ndarray:
var x = array( buf, {
'shape': [ 3, 3, 3 ]
});
// Get each matrix...
var y1 = sliceDimension( x, 0, 0 );
// returns <ndarray>
var a1 = ndarray2array( y1 );
// returns [ [ 0, 1, 2 ], [ 3, 4, 5 ], [ 6, 7, 8 ] ]
var y2 = sliceDimension( x, 0, 1 );
// returns <ndarray>
var a2 = ndarray2array( y2 );
// returns [ [ 9, 10, 11 ], [ 12, 13, 14 ], [ 15, 16, 17 ] ]
var y3 = sliceDimension( x, 0, 2 );
// returns <ndarray>
var a3 = ndarray2array( y3 );
// returns [ [ 18, 19, 20 ], [ 21, 22, 23 ], [ 24, 25, 26 ] ]
// Reverse the matrix order:
var s = S( _, _, -1 );
var y4 = sliceDimension( x, 0, s );
// returns <ndarray>
var a4 = ndarray2array( y4 );
// returns [...]
// Get the second rows from each matrix:
var y5 = sliceDimension( x, 1, 1 );
// returns <ndarray>
var a5 = ndarray2array( y5 );
// returns [ [ 3, 4, 5 ], [ 12, 13, 14 ], [ 21, 22, 23 ] ]
// Get the second columns from each matrix:
var y6 = sliceDimension( x, 2, 1 );
// returns <ndarray>
var a6 = ndarray2array( y6 );
// returns [ [ 1, 4, 7 ], [ 10, 13, 16 ], [ 19, 22, 25 ] ]
@stdlib/ndarray-array
: multidimensional arrays.
@stdlib/ndarray-ctor
: multidimensional array constructor.
@stdlib/ndarray-slice
: return a read-only view of an input ndarray.
@stdlib/ndarray-slice-dimension-from
: return a read-only shifted view of an input ndarray along a specific dimension.
@stdlib/ndarray-slice-dimension-to
: return a read-only truncated view of an input ndarray along a specific dimension.
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