random-picker

Description

Randomly pick an item from a set (using the specified probabilities).

Getting Started

Install the module with: npm install random-picker

var Picker = require('random-picker').Picker;
var picker = new Picker(); // or pass in a seed: var picker = new Picker(seed)
picker.option('male');
picker.option('female');
picker.pick(); // 50% chance of being 'male' or 'female'
picker.option('male', 22);
picker.option('female', 78);
picker.pick(); // now there's a 22% chance of being 'male', and a 78% change of being 'female'
picker.removeAll();
picker.option('good', 3.42)
picker.option('bad', 3.42)
picker.pick(); // now there's a 50% chance of being 'good' or 'bad'

• Live example on Tonic

Documentation

pick()

Randomly pick an item from the options that were added. The probability of an item being chosen is determined by the score that was given to the option.

option(value, score)

Add an item to the list of available options that can be picked. A default score of 1 is used if the score is not passed in.

removeAll()

Remove all the options that have been passed in.

remove(value)

Remove the given option if it exists.

size()

Return how many options have been passed in.

totalScore()

What is the total score of the existing options?

avgScore()

What is the average score of the existing options?

Examples

Initialize a picker with a given seed:

var picker = require('random-picker').Picker('Seed my random generator');

A random score of 1 is used by default:

// if male/female are the only options, then the following:
picker.option('male');
picker.option('female');
// is the same as:
picker.option('male', 1);
picker.option('female', 1);
// or for that matter:
picker.option('male', 100);
picker.option('female', 100);

You can pass in functions as well. The following code will return a random number 80% of the time, and 0.5 20% of the time:

picker.option(function () {
    return Math.random();
}, 80);
picker.option(function () {
    return 0.5;
}, 20);
console.log(picker.pick()());

Release History

Version 0.1.0 (Released June 4, 2014)

• initial release

License

Copyright (c) 2014 skratchdot
Licensed under the MIT license.