npm package: @stdlib/stats-strided-nanmidrange
Description: Calculate the mid-range of a strided array, ignoring NaN values.
Author: The Stdlib Authors
Latest version: 0.1.1

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

# nanmidrange

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

> Calculate the [mid-range][mid-range] of a strided array, ignoring `NaN` values.

<section class="intro">

The [**mid-range**][mid-range], or **mid-extreme**, is the arithmetic mean of the maximum and minimum values in a data set. The measure is the midpoint of the range and a measure of central tendency.

</section>

<!-- /.intro -->

<section class="installation">

## Installation

```bash
npm install @stdlib/stats-strided-nanmidrange
```

</section>

<section class="usage">

## Usage

```javascript
var nanmidrange = require( '@stdlib/stats-strided-nanmidrange' );
```

#### nanmidrange( N, x, strideX )

Computes the [mid-range][mid-range] of a strided array, ignoring `NaN` values.

```javascript
var x = [ 1.0, -2.0, NaN, 2.0 ];
var N = x.length;

var v = nanmidrange( N, x, 1 );
// returns 0.0
```

The function has the following parameters:

-   **N**: number of indexed elements.
-   **x**: input [`Array`][mdn-array] or [`typed array`][mdn-typed-array].
-   **strideX**: stride length for `x`.

The `N` and stride parameters determine which elements in the strided array are accessed at runtime. For example, to compute the [mid-range][mid-range] of every other element in `x`,

```javascript
var x = [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0, NaN, NaN ];

var v = nanmidrange( 5, x, 2 );
// returns 1.0
```

Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.

<!-- eslint-disable stdlib/capitalized-comments, max-len -->

```javascript
var Float64Array = require( '@stdlib/array-float64' );

var x0 = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, NaN, NaN, 4.0 ] );
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var v = nanmidrange( 4, x1, 2 );
// returns 1.0
```

#### nanmidrange.ndarray( N, x, strideX, offsetX )

Computes the [mid-range][mid-range] of a strided array, ignoring `NaN` values and using alternative indexing semantics.

```javascript
var x = [ 1.0, -2.0, NaN, 2.0 ];
var N = x.length;

var v = nanmidrange.ndarray( N, x, 1, 0 );
// returns 0.0
```

The function has the following additional parameters:

-   **offsetX**: starting index for `x`.

While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to calculate the [mid-range][mid-range] for every other element in the strided array starting from the second element

```javascript
var x = [ 2.0, 1.0, 2.0, -2.0, -2.0, NaN, NaN, 2.0, 3.0, 4.0 ];

var v = nanmidrange.ndarray( 5, x, 2, 1 );
// returns 1.0
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   If `N <= 0`, both functions return `NaN`.
-   Both functions support array-like objects having getter and setter accessors for array element access (e.g., [`@stdlib/array-base/accessor`][@stdlib/array/base/accessor]).
-   Depending on the environment, the typed versions ([`dnanmidrange`][@stdlib/stats/strided/dnanmidrange], [`snanmidrange`][@stdlib/stats/strided/snanmidrange], etc.) are likely to be significantly more performant.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var uniform = require( '@stdlib/random-base-uniform' );
var filledarrayBy = require( '@stdlib/array-filled-by' );
var bernoulli = require( '@stdlib/random-base-bernoulli' );
var nanmidrange = require( '@stdlib/stats-strided-nanmidrange' );

function rand() {
    if ( bernoulli( 0.8 ) < 1 ) {
        return NaN;
    }
    return uniform( -50.0, 50.0 );
}

var x = filledarrayBy( 10, 'float64', rand );
console.log( x );

var v = nanmidrange( x.length, x, 1 );
console.log( v );
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. -->

<section class="related">

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->


<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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[coverage-url]: https://codecov.io/github/stdlib-js/stats-strided-nanmidrange?branch=main

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[stdlib]: https://github.com/stdlib-js/stdlib

[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors

[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/stats-strided-nanmidrange/tree/deno
[deno-readme]: https://github.com/stdlib-js/stats-strided-nanmidrange/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/stats-strided-nanmidrange/tree/umd
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[branches-url]: https://github.com/stdlib-js/stats-strided-nanmidrange/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/stats-strided-nanmidrange/main/LICENSE

[mid-range]: https://en.wikipedia.org/wiki/Mid-range

[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array

[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

[@stdlib/array/base/accessor]: https://www.npmjs.com/package/@stdlib/array-base-accessor

[@stdlib/stats/strided/dnanmidrange]: https://www.npmjs.com/package/@stdlib/stats-strided-dnanmidrange

[@stdlib/stats/strided/snanmidrange]: https://www.npmjs.com/package/@stdlib/stats-strided-snanmidrange

</section>

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