Gallery

Modules

Documentation

Context Navigation

YUI Library is not responsible for bugs or support with this module. It is available as a free service. For support please contact the module owner with the provided links.

Weighted List (gallery-weighted-list) on cdn

Last Updated: 07/15/12

+ 0 -

Steven Olmsted

YUI Contributor

See 42 more by this user.

Created: 07/14/12
Last CDN Push: 05/2/13
Build Tag: gallery-2013.05.02-22-59
Project: YUI 3
License: YUI BSD
YUI Version: 3.5.1
Free for use.

Y.WeightedList has many features similar to an array list and can generally function as one. Every value in a weighted list also has a weight value attached to it. Values can be retrieved from a weighted list by index as you would expect, but values can also be retrieved at random. The probability of any value being selected at random is weighted. For example, a value with a weight of 500 is twice as likely to be selected as a value with a weight of 250.

If gallery-alea is present, it will be used for random number generation instead of Math.random.

Download
Docs
Homepage
Bugs
Source
Example
Forum
History

When the total sum of all weights in the list is 0, random selection will not work and will return null. Negative weights can yield unexpected results.

Code Sample

<script src="http://yui.yahooapis.com/3.5.1/build/yui/yui-min.js"></script>

YUI({
    //Last Gallery Build of this module
    gallery: 'gallery-2013.05.02-22-59'
}).use('gallery-alea', 'gallery-weighted-list', function(Y) {
    // Create a new list.
    var list = new Y.WeightedList(),
        value;
 
    // Add some weighted values to the list.
    list.add('value 1', 5.5);
    list.add('value 2', 10);
    list.add('value 3', 2.5);
 
    // Get a value randomly from the list.
    value = list.value();
 
    // There is about a 30% chance that value === 'value 1'.
    // There is about a 56% chance that value === 'value 2'.
    // There is about a 14% chance that value === 'value 3'.
});