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Create an iterator which iterates over each column in a matrix (or stack of matrices).
import nditerColumns from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-iter-columns@esm/index.mjs';Returns an iterator which iterates over each column in a matrix (or stack of matrices).
import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@esm/index.mjs';
import ndarray2array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-to-array@esm/index.mjs';
var x = array( [ [ [ 1, 2 ], [ 3, 4 ] ], [ [ 5, 6 ], [ 7, 8 ] ] ] );
// returns <ndarray>
var iter = nditerColumns( x );
var v = iter.next().value;
// returns <ndarray>
var arr = ndarray2array( v );
// returns [ 1, 3 ]
v = iter.next().value;
// returns <ndarray>
arr = ndarray2array( v );
// returns [ 2, 4 ]
v = iter.next().value;
// returns <ndarray>
arr = ndarray2array( v );
// returns [ 5, 7 ]
// ...The function accepts the following options:
- readonly: boolean indicating whether returned
ndarrayviews should be read-only. In order to return writablendarrayviews, the inputndarraymust be writable. If the inputndarrayis read-only, setting this option tofalseraises an exception. Default:true.
By default, the iterator returns ndarray views which are read-only. To return writable views, set the readonly option to false.
import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@esm/index.mjs';
import ndarray2array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-to-array@esm/index.mjs';
var x = array( [ [ [ 1, 2 ], [ 3, 4 ] ], [ [ 5, 6 ], [ 7, 8 ] ] ] );
// returns <ndarray>
var iter = nditerColumns( x, {
'readonly': false
});
var v = iter.next().value;
// returns <ndarray>
var arr = ndarray2array( v );
// returns [ 1, 3 ]
v.set( 0, 10 );
arr = ndarray2array( v );
// returns [ 10, 3 ]The returned iterator protocol-compliant object has the following properties:
- next: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a
valueproperty and adoneproperty having abooleanvalue indicating whether the iterator is finished. - return: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.
- If an environment supports
Symbol.iterator, the returned iterator is iterable. - A returned iterator does not copy a provided
ndarray. To ensure iterable reproducibility, copy the inputndarraybefore creating an iterator. Otherwise, any changes to the contents of inputndarraywill be reflected in the returned iterator. - In environments supporting
Symbol.iterator, the function explicitly does not invoke an ndarray's@@iteratormethod, regardless of whether this method is defined.
<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">
import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@esm/index.mjs';
import zeroTo from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-base-zero-to@esm/index.mjs';
import ndarray2array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-to-array@esm/index.mjs';
import nditerColumns from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-iter-columns@esm/index.mjs';
// Define an input array:
var x = array( zeroTo( 27 ), {
'shape': [ 3, 3, 3 ]
});
// Create an iterator for iterating over columns:
var it = nditerColumns( x );
// Perform manual iteration...
var v;
while ( true ) {
v = it.next();
if ( v.done ) {
break;
}
console.log( ndarray2array( v.value ) );
}
</script>
</body>
</html>@stdlib/ndarray-iter/column-entries: create an iterator which returns [index, column] pairs for each column in a matrix (or stack of matrices).@stdlib/ndarray-iter/rows: create an iterator which iterates over each row in a matrix (or stack of matrices).@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.
Copyright © 2016-2025. The Stdlib Authors.
