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Return an
ndarrayelement.
import at from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-at@esm/index.mjs';Returns an ndarray element.
import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@esm/index.mjs';
var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
// returns <ndarray>
var v = at( x, 0, 0 );
// returns 1
v = at( x, 0, 1 );
// returns 2
v = at( x, 1, 0 );
// returns 3
v = at( x, 1, 1 );
// returns 4The function accepts the following arguments:
- x: input
ndarray. - indices: index arguments. The number of index arguments must equal the number of dimensions.
-
If provided out-of-bounds indices, the function always returns
undefined.import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@esm/index.mjs'; var x = array( [ [ 1, 2 ], [ 3, 4 ] ] ); // returns <ndarray> var v = at( x, 10, 20 ); // returns undefined
-
Negative indices are resolved relative to the last element along the respective dimension, with the last element corresponding to
-1.import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@esm/index.mjs'; var x = array( [ [ 1, 2 ], [ 3, 4 ] ] ); // returns <ndarray> var v = at( x, -1, -1 ); // returns 4 v = at( x, -2, -2 ); // returns 1
<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">
import cartesianProduct from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-cartesian-product@esm/index.mjs';
import zeroTo from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-zero-to@esm/index.mjs';
import discreteUniform from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-array-discrete-uniform@esm/index.mjs';
import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@esm/index.mjs';
import at from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-at@esm/index.mjs';
// Define a two-dimensional array:
var shape = [ 5, 5 ];
var x = array( discreteUniform( 25, -100, 100 ), {
'shape': shape
});
// Define lists of dimension indices:
var i0 = zeroTo( shape[ 0 ], 'generic' );
var i1 = zeroTo( shape[ 1 ], 'generic' );
// Create a list of index pairs:
var indices = cartesianProduct( i0, i1 );
// Print array contents...
var idx;
var i;
for ( i = 0; i < x.length; i++ ) {
idx = indices[ i ];
console.log( 'x[%d,%d] = %d', idx[ 0 ], idx[ 1 ], at( x, idx[ 0 ], idx[ 1 ] ) );
}
</script>
</body>
</html>@stdlib/ndarray-array: multidimensional arrays.@stdlib/ndarray-slice: return a read-only view of an input ndarray.
This package is part of stdlib, a standard library 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.
See LICENSE.
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