pick-weight

Returns a single item from an array with relative weighting of odds.

Install

$ npm install --save pick-weight 

Usage

var weighted = require('pick-weight');
  
// API
// - weighted(arr, weights);

The following code will generate 'a' 100 times more often than 'b' but still choose one or the other randomly.

weighted(['a', 'b'], [100, 1]);
// => 'a'

The weights are all relative, so if you have more than just two it will ensure that all items are generated relative to all of the weights.

weighted(['a', 'b', 'c', 'd'], [1, 2, 3, 4]);
// => 'c'

Will generate a letter from the array but will pick 'b' twice as often as it picks 'a' and will pick 'c' three times as often as it picks 'a' and will pick 'd' four times as often as it will pick 'a' and will pick 'd' two times as often as it will pick 'b'.

The weights can be whole numbers as shown above or fractions.

weighted(['a', 'b', 'c', 'd'], [0.1, 0.2, 0.3, 0.4]);
// => 'd'

There is no requirement that the weights sum to anything in particular, they are all compared relative to each other so all of the following are equivalent:

weighted(['a', 'b', 'c', 'd'], [1, 2, 3, 4]);
weighted(['a', 'b', 'c', 'd'], [0.1, 0.2, 0.3, 0.4]);
weighted(['a', 'b', 'c', 'd'], [100, 200, 300, 400]);
weighted(['a', 'b', 'c', 'd'], [17, 34, 51, 68]);
weighted(['a', 'b', 'c', 'd'], [0.17, 0.34, 0.51, 0.68]);

Related

• pick-item - Given an array, pick a random element and return it.
• pick-items - Given an array, pick some random elements and return them in a new array.
• pick-prop - Given an object, pick a random property and return it.
• pick-props - Given an object, pick some random properties and return them in an array.
• pick-key - Given an object, pick a random key and return it.
• pick-keys - Given an object, pick some random keys and return them in an array.
• pick-pair - Given an object, pick a random key-value and return it in a new object.
• pick-pairs - Given an object, pick some random key-values and return it in a new object.

Contributing

Pull requests and stars are highly welcome.

For bugs and feature requests, please create an issue.