npm package: @stdlib/iter-strided
Description: Create an iterator which steps by a specified amount.
Author: The Stdlib Authors
Latest version: 0.2.3

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<details>
  <summary>
    About stdlib...
  </summary>
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</details>

# iterStrided

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> Create an [iterator][mdn-iterator-protocol] which steps by a specified amount.

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/iter-strided
```

</section>

<section class="usage">

## Usage

```javascript
var iterStrided = require( '@stdlib/iter-strided' );
```

#### iterStrided( iterator, stride\[, offset\[, eager]] )

Returns an [iterator][mdn-iterator-protocol] which steps by a specified amount.

```javascript
var array2iterator = require( '@stdlib/array-to-iterator' );

var arr = array2iterator( [ 1, 2, 3, 4, 5, 6, 7, 8 ] );
var it = iterStrided( arr, 2 );
// returns <Object>

var r = it.next().value;
// returns 1

r = it.next().value;
// returns 3

r = it.next().value;
// returns 5

// ...
```

The returned [iterator][mdn-iterator-protocol] protocol-compliant object has the following properties:

-   **next**: function which returns an [iterator][mdn-iterator-protocol] 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][mdn-iterator-protocol] and returns a single (optional) argument in an [iterator][mdn-iterator-protocol] protocol-compliant object.

To skip the first `N` values of a provided [`iterator`][mdn-iterator-protocol], provide an `offset` argument.

```javascript
var array2iterator = require( '@stdlib/array-to-iterator' );

var arr = array2iterator( [ 1, 2, 3, 4, 5, 6, 7, 8 ] );
var it = iterStrided( arr, 2, 1 );
// returns <Object>

var r = it.next().value;
// returns 2

r = it.next().value;
// returns 4

r = it.next().value;
// returns 6

// ...
```

By default, the returned [iterator][mdn-iterator-protocol] defers consuming the first `N` input [`iterator`][mdn-iterator-protocol] values until the first value of the returned [iterator][mdn-iterator-protocol] is consumed. To eagerly advance the input [`iterator`][mdn-iterator-protocol], set the `eager` argument to `true`.

```javascript
var array2iterator = require( '@stdlib/array-to-iterator' );

var arr = array2iterator( [ 1, 2, 3, 4, 5, 6, 7, 8 ] );
var it = iterStrided( arr, 1, 4, true );
// returns <Object>

var r = it.next().value;
// returns 5

r = it.next().value;
// returns 6

r = it.next().value;
// returns 7

// ...
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   If an environment supports `Symbol.iterator` **and** a provided [iterator][mdn-iterator-protocol] is iterable, the returned [iterator][mdn-iterator-protocol] is iterable.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var randu = require( '@stdlib/random-iter-randu' );
var iterStrided = require( '@stdlib/iter-strided' );

// Create a seeded iterator for generating pseudorandom numbers:
var rand = randu({
    'seed': 1234,
    'iter': 10
});

// Create an iterator which returns every other random number:
var it = iterStrided( rand, 2 );

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

</section>

<!-- /.examples -->

<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="references">

</section>

<!-- /.references -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/iter-advance`][@stdlib/iter/advance]</span><span class="delimiter">: </span><span class="description">advance an iterator.</span>
-   <span class="package-name">[`@stdlib/iter-nth`][@stdlib/iter/nth]</span><span class="delimiter">: </span><span class="description">return the nth iterated value.</span>
-   <span class="package-name">[`@stdlib/iter-strided-by`][@stdlib/iter/strided-by]</span><span class="delimiter">: </span><span class="description">create an iterator which steps according to a provided callback function.</span>

</section>

<!-- /.related -->

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<section class="main-repo" >

* * *

## Notice

This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

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[test-url]: https://github.com/stdlib-js/iter-strided/actions/workflows/test.yml?query=branch:v0.2.3

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/iter-strided/main.svg
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[stdlib]: https://github.com/stdlib-js/stdlib

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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/iter-strided/tree/deno
[deno-readme]: https://github.com/stdlib-js/iter-strided/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/iter-strided/tree/umd
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/iter-strided/main/LICENSE

[mdn-iterator-protocol]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#The_iterator_protocol

<!-- <related-links> -->

[@stdlib/iter/advance]: https://www.npmjs.com/package/@stdlib/iter-advance

[@stdlib/iter/nth]: https://www.npmjs.com/package/@stdlib/iter-nth

[@stdlib/iter/strided-by]: https://www.npmjs.com/package/@stdlib/iter-strided-by

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</section>

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