Zip

Generate array tuples from input arrays.

Installation

npm install @stdlib/utils-zip

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

// Default behavior:
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' ) );

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.

Zip