stdlib-js/utils-zip

Generate array tuples from input arrays.

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.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

Zip

Generate array tuples from input arrays.

Installation

npm install @stdlib/utils-zip

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 zip = require( '@stdlib/utils-zip' );

zip( arr1, arr2,...[, opts] )

Returns an array of arrays, where the ith element (tuple) in the returned array contains the ith elements of the input arrays.

var zipped = zip( [ 1, 2 ], [ 'a', 'b' ] );
// returns [ [ 1, 'a' ], [ 2, 'b' ] ]

By default, the returned array length is the length of the shortest input array.

var zipped = zip( [ 1, 2, 3 ], [ 'a', 'b' ] );
// returns [ [ 1, 'a' ], [ 2, 'b' ] ]

The function accepts an options object with optional properties:

• trunc: boolean specifying whether the returned array should truncate arrays longer than the shortest array. Default: true.
• fill: fill value used for unequal length arrays. Default: null.
• arrays: boolean specifying whether, when provided a single input array, the function should interpret the argument as a list of arrays to be zipped (i.e., behavior similar to zip.apply(null, arr)). Default: false.

To turn off truncation,

var opts = {
    'trunc': false
};

var zipped = zip( [ 1, 2, 3 ], [ 'a', 'b' ], opts );
// returns [ [ 1, 'a' ], [ 2, 'b' ], [ 3, null ] ]

A fill value is included in each tuple for each array which does not have an element at the ith index. By default, the fill value is null. To specify a different fill value, set the fill option.

var opts = {
    'trunc': false,
    'fill': ''
};

var zipped = zip( [ 1, 2, 3 ], [ 'a', 'b' ], opts );
// returns [ [ 1, 'a' ], [ 2, 'b' ], [ 3, '' ] ]

If the function should interpret a single input array as an array of arrays to be zipped,

var arr = [ [ 1, 2 ], [ 'a', 'b' ] ];

// Default behavior:
var zipped = zip( arr );
// returns [ [ [ 1, 2 ] ], [ [ 'a', 'b' ] ] ]

// Array of arrays:
zipped = zip( arr, { 'arrays': true } );
// returns [ [ 1, 'a' ], [ 2, 'b' ] ]

Examples

var randu = require( '@stdlib/random-base-randu' );
var zip = require( '@stdlib/utils-zip' );

var x = [];
var y1 = [];
var y2 = [];
var y3 = [];

// Simulate some data...
var i;
for ( i = 0; i < 100; i++ ) {
    x.push( Date.now() );
    y1.push( randu() * 100 );
    y2.push( randu() * 100 );
    y3.push( randu() );
}

var zipped = zip( x, y1, y2, y3 );

console.log( zipped.join( '\n' ) );

---

See Also

• @stdlib/utils-unzip: unzip a zipped array (i.e., a nested array of tuples).

---

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

---

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.