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nditerValues

Create an iterator which returns individual elements from a provided ndarray.

Installation

npm install @stdlib/ndarray-iter-values

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var nditerValues = require( '@stdlib/ndarray-iter-values' );

nditerValues( x[, options] )

Returns an iterator which returns individual elements from a provided ndarray.

var array = require( '@stdlib/ndarray-array' );

var x = array( [ [ [ 1, 2 ], [ 3, 4 ] ], [ [ 5, 6 ], [ 7, 8 ] ] ] );
// returns <ndarray>

var iter = nditerValues( x );

var v = iter.next().value;
// returns 1

v = iter.next().value;
// returns 2

v = iter.next().value;
// returns 3

// ...

The function accepts the following options:

• order: index iteration order. By default, the returned iterator returns values according to the layout order of the provided array. Accordingly, for row-major input arrays, the last dimension indices increment fastest. For column-major input arrays, the first dimension indices increment fastest. To override the inferred order and ensure that indices increment in a specific manor, regardless of the input array's layout order, explicitly set the iteration order. Note, however, that iterating according to an order which does not match that of the input array may, in some circumstances, result in performance degradation due to cache misses. Must be either 'row-major' or 'column-major'.

By default, the iterator iterates according to the layout order of the input ndarray. To iterate according to a specified order, set the order option.

var array = require( '@stdlib/ndarray-array' );

var x = array( [ [ [ 1, 2 ], [ 3, 4 ] ], [ [ 5, 6 ], [ 7, 8 ] ] ], {
    'order': 'row-major'
});
// returns <ndarray>

var iter = nditerValues( x, {
    'order': 'column-major'
});

var v = iter.next().value;
// returns 1

v = iter.next().value;
// returns 5

v = iter.next().value;
// returns 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 value property and a done property having a boolean value indicating whether the iterator is finished.
• return: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.

Notes

• 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 input ndarray before creating an iterator. Otherwise, any changes to the contents of input ndarray will be reflected in the returned iterator.
• In environments supporting Symbol.iterator, the function explicitly does not invoke an ndarray's @@iterator method, regardless of whether this method is defined.

Examples

var array = require( '@stdlib/ndarray-array' );
var zeroTo = require( '@stdlib/array-base-zero-to' );
var nditerValues = require( '@stdlib/ndarray-iter-values' );

// Define an input array:
var x = array( zeroTo( 27 ), {
    'shape': [ 3, 3, 3 ]
});

// Create an iterator for returning individual elements:
var it = nditerValues( x );

// Perform manual iteration...
var v;
while ( true ) {
    v = it.next();
    if ( v.done ) {
        break;
    }
    console.log( v.value );
}

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See Also

• @stdlib/ndarray-ctor: multidimensional array constructor.
• @stdlib/ndarray-iter/entries: create an iterator which returns [index, value] pairs for each element in a provided ndarray.
• @stdlib/ndarray-iter/indices: create an iterator which returns indices for use indexing into an ndarray having a specified shape.

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Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, 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.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.