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Create a filled two-dimensional symmetric nested array according to a provided callback function.
import filled2dBy from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-base-symmetric-filled2d-by@esm/index.mjs';Returns a filled two-dimensional symmetric nested array according to a provided callback function.
function clbk( idx ) {
return idx[ 0 ] + idx[ 1 ];
}
var out = filled2dBy( 2, clbk );
// returns [ [ 0, 1 ], [ 1, 2 ] ]The function accepts the following arguments:
- N: number of rows and columns.
- clbk: callback function.
- thisArg: callback function execution context (optional).
When invoked, a callback function is provided a single argument:
- indices: current array element indices.
To set the callback execution context, provide a thisArg.
function clbk() {
this.count += 1;
return 1;
}
var ctx = {
'count': 0
};
var out = filled2dBy( 2, clbk, ctx );
// returns [ [ 1, 1 ], [ 1, 1 ] ];
var cnt = ctx.count;
// returns 3- As the output array is symmetric, the callback function is only invoked for the elements residing in the upper triangle of the output array (i.e.,
indices[1] >= indices[0]).
<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">
import constantFunction from 'https://cdn.jsdelivr.net/gh/stdlib-js/utils-constant-function@esm/index.mjs';
import filled2dBy from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-base-symmetric-filled2d-by@esm/index.mjs';
var out = filled2dBy( 2, constantFunction( 0.0 ) );
// returns [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ]
out = filled2dBy( 2, constantFunction( 'beep' ) );
// returns [ [ 'beep', 'beep' ], [ 'beep', 'beep' ] ]
out = filled2dBy( 2, constantFunction( null ) );
// returns [ [ null, null ], [ null, null ] ]
out = filled2dBy( 2, constantFunction( true ) );
// returns [ [ true, true ], [ true, true ] ]
function clbk( indices ) {
return indices[ 0 ] + indices[ 1 ];
}
out = filled2dBy( 3, clbk );
// returns [ [ 0, 1, 2 ], [ 1, 2, 3 ], [ 2, 3, 4 ] ]
</script>
</body>
</html>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.
Copyright © 2016-2025. The Stdlib Authors.
