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stdlib/lib/node_modules/@stdlib/utils/zip at develop · stdlib-js/stdlib

Generate array tuples from input arrays.

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