npm package: @stdlib/array-base-count-ifs
Description: Perform element-wise evaluation of one or more input arrays according to provided predicate functions and count the number of elements for which all predicates respectively return `true`.
Author: The Stdlib Authors
Latest version: 0.1.1

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# countIfs

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

> Perform element-wise evaluation of one or more input arrays according to provided predicate functions and count the number of elements for which all predicates respectively return `true`.

<!-- 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>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/array-base-count-ifs
```

</section>

<section class="usage">

## Usage

```javascript
var countIfs = require( '@stdlib/array-base-count-ifs' );
```

#### countIfs( x0, predicate0\[, x1, predicate1\[, x2, predicate2\[, ...args]]] )

Performs element-wise evaluation of one or more input arrays according to provided predicate functions and counts the number of elements for which all predicates respectively return `true`.

```javascript
function predicate0( value ) {
    return ( value > 0 );
}

function predicate1( value ) {
    return ( value < 3 );
}

var x0 = [ 0, 1, 0, 1, 2 ];
var x1 = [ 2, 3, 1, 2, 5 ];

var out = countIfs( x0, predicate0, x1, predicate1 );
// returns 1
```

The function has the following parameters:

-   **x0**: first input array.
-   **predicate0**: first predicate function.
-   **x1**: second input array (_optional_).
-   **predicate1**: second predicate function (_optional_).
-   **x2**: third input array (_optional_).
-   **predicate2**: third predicate function (_optional_).
-   **args**: additional input arrays and corresponding predicate functions (_optional_).

Each predicate function is provided three arguments:

-   **value**: current array element.
-   **index**: current array element index.
-   **arr**: the corresponding input array.

</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

-   The function assumes that all input arrays have the same length.
-   The function supports array-like objects supporting the accessor protocol (e.g., [`Complex128Array`][@stdlib/array/complex128], [`Complex64Array`][@stdlib/array/complex64], etc).

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

<!-- eslint-disable max-len -->

```javascript
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var isPositiveInteger = require( '@stdlib/assert-is-positive-integer' ).isPrimitive;
var isNegativeInteger = require( '@stdlib/assert-is-negative-integer' ).isPrimitive;
var naryFunction = require( '@stdlib/utils-nary-function' );
var countIfs = require( '@stdlib/array-base-count-ifs' );

var x = discreteUniform( 10, -5, 5, {
    'dtype': 'int32'
});
console.log( x );

var y = discreteUniform( 10, -5, 5, {
    'dtype': 'int32'
});
console.log( y );

var out = countIfs( x, naryFunction( isPositiveInteger, 1 ), y, naryFunction( isNegativeInteger, 1 ) );
console.log( out );
```

</section>

<!-- /.examples -->

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<section class="related">

</section>

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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

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---

## License

See [LICENSE][stdlib-license].


## Copyright

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

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[deno-url]: https://github.com/stdlib-js/array-base-count-ifs/tree/deno
[deno-readme]: https://github.com/stdlib-js/array-base-count-ifs/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/array-base-count-ifs/tree/umd
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[esm-url]: https://github.com/stdlib-js/array-base-count-ifs/tree/esm
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[branches-url]: https://github.com/stdlib-js/array-base-count-ifs/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/array-base-count-ifs/main/LICENSE

[@stdlib/array/complex128]: https://www.npmjs.com/package/@stdlib/array-complex128

[@stdlib/array/complex64]: https://www.npmjs.com/package/@stdlib/array-complex64

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