# sliceDimensionFrom
> Return a read-only shifted view of an input [`ndarray`][@stdlib/ndarray/ctor] along a specified dimension.
## Usage
```javascript
var sliceDimensionFrom = require( '@stdlib/ndarray/slice-dimension-from' );
```
#### sliceDimensionFrom( x, dim, start\[, options] )
Returns a **read-only** shifted view of an input [`ndarray`][@stdlib/ndarray/ctor] along a specified dimension.
```javascript
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
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 y = sliceDimensionFrom( x, 0, 1 );
// returns
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`][@stdlib/ndarray/ctor].
- **dim**: index of dimension along which to slice. If provided an integer less than zero, the dimension index is resolved relative to the last dimension, with the last dimension corresponding to the value `-1`.
- **start**: starting index (inclusive). 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`.
- **options**: function options.
The function supports the following `options`:
- **strict**: boolean indicating whether to enforce strict bounds checking.
By default, the function throws an error when provided a starting index which exceeds array bounds. To return an empty array when a starting index exceeds array bounds, set the `strict` option to `false`.
```javascript
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
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 y = sliceDimensionFrom( x, 1, 20, {
'strict': false
});
// returns
sh = y.shape;
// returns [ 3, 0 ]
arr = ndarray2array( y );
// returns []
```
## Examples
```javascript
var array = require( '@stdlib/ndarray/array' );
var ndarray2array = require( '@stdlib/ndarray/to-array' );
var zeroTo = require( '@stdlib/array/base/zero-to' );
var sliceDimensionFrom = require( '@stdlib/ndarray/slice-dimension-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 = sliceDimensionFrom( x, 1, 1 );
// returns
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 columns of each matrix:
var y2 = sliceDimensionFrom( x, 2, 1 );
// returns
var a2 = ndarray2array( y2 );
// returns [ [ [ 1, 2 ], [ 4, 5 ], [ 7, 8 ] ], [ [ 10, 11 ], [ 13, 14 ], [ 16, 17 ] ], [ [ 19, 20 ], [ 22, 23 ], [ 25, 26 ] ] ]
// Get the last two matrices:
var y3 = sliceDimensionFrom( x, 0, 1 );
// returns
var a3 = ndarray2array( y3 );
// returns [ [ [ 9, 10, 11 ], [ 12, 13, 14 ], [ 15, 16, 17 ] ], [ [ 18, 19, 20 ], [ 21, 22, 23 ], [ 24, 25, 26 ] ] ]
```
[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/ndarray/tree/main/ctor
[@stdlib/ndarray/array]: https://github.com/stdlib-js/ndarray/tree/main/array
[@stdlib/ndarray/slice]: https://github.com/stdlib-js/ndarray/tree/main/slice
[@stdlib/ndarray/slice-dimension]: https://github.com/stdlib-js/ndarray/tree/main/slice-dimension
[@stdlib/ndarray/slice-dimension-to]: https://github.com/stdlib-js/ndarray/tree/main/slice-dimension-to
[@stdlib/ndarray/slice-from]: https://github.com/stdlib-js/ndarray/tree/main/slice-from