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About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

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bifurcateEntriesBy

NPM version Build Status Coverage Status

Split element entries into two groups according to a predicate function.

Usage

import bifurcateEntriesBy from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-base-bifurcate-entries-by@esm/index.mjs';

bifurcateEntriesBy( x, predicate[, thisArg] )

Splits element entries into two groups according to a predicate function.

function predicate( v ) {
    return v[ 0 ] === 'b';
}

var x = [ 'beep', 'boop', 'foo', 'bar' ];

var out = bifurcateEntriesBy( x, predicate );
// returns [ [ [ 0, 'beep' ], [ 1, 'boop' ], [ 3, 'bar' ] ], [ [ 2, 'foo' ] ] ]

A predicate function is provided the following arguments:

  • value: current array element.
  • index: current array element index.
  • arr: input array.

To set the predicate function execution context, provide a thisArg.

function predicate( v ) {
    this.count += 1;
    return v[ 0 ] === 'b';
}

var x = [ 'beep', 'boop', 'foo', 'bar' ];

var context = {
    'count': 0
};
var out = bifurcateEntriesBy( x, predicate, context );
// returns [ [ [ 0, 'beep' ], [ 1, 'boop' ], [ 3, 'bar' ] ], [ [ 2, 'foo' ] ] ]

var cnt = context.count;
// returns 4

Examples

<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">

import discreteUniform from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-array-discrete-uniform@esm/index.mjs';
import take from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-base-take-indexed@esm/index.mjs';
import bifurcateEntriesBy from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-base-bifurcate-entries-by@esm/index.mjs';

function predicate( v ) {
    // Use the first letter of each element to define groups:
    return v[ 0 ] === 'b';
}

// Define an initial array of values:
var values = [ 'beep', 'boop', 'foo', 'bar', 'woot', 'woot' ];

// Sample from the initial array to generate a random collection:
var indices = discreteUniform( 100, 0, values.length-1, {
    'dtype': 'generic'
});
var x = take( values, indices );
// returns [...]

// Split the values:
var out = bifurcateEntriesBy( x, predicate );
// returns [...]

console.log( out );

</script>
</body>
</html>

Notice

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.

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.