tabulate

Generate a frequency table.

Installation

npm install @stdlib/utils-tabulate

Usage

var tabulate = require( '@stdlib/utils-tabulate' );

tabulate( collection )

Generates a frequency table.

var arr = [ 'beep', 'boop', 'foo', 'beep' ];

var out = tabulate( arr );
// returns [ [ 'beep', 2, 0.5 ], [ 'boop', 1, 0.25 ], [ 'foo', 1, 0.25 ] ]

The returned frequency table is an array of arrays. Each sub-array corresponds to a unique value in the input collection and is structured as follows:

• 0: unique value
• 1: value count
• 2: frequency percentage

Notes

• A collection may be either an Array, Typed Array, or an array-like Object (excluding strings and functions).

Examples

var randu = require( '@stdlib/random-base-randu' );
var floor = require( '@stdlib/math-base-special-floor' );
var tabulate = require( '@stdlib/utils-tabulate' );

var vals;
var arr;
var out;
var i;
var j;

vals = [ 'beep', 'boop', 'foo', 'bar', 'woot', 'woot' ];

// Generate a random collection...
arr = new Array( 100 );
for ( i = 0; i < arr.length; i++ ) {
    j = floor( randu()*vals.length );
    arr[ i ] = vals[ j ];
}

// Generate a frequency table:
out = tabulate( arr );
console.log( out );

See Also

• @stdlib/utils-count-by: group values according to an indicator function and return group counts.
• @stdlib/utils-group-by: group values according to an indicator function.
• @stdlib/utils-tabulate-by: generate a frequency table according to an indicator function.

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.