(Python) algorithm to randomly select a key based on proportionality/weight

Question

I\'m a bit at a loss as to how to find a clean algorithm for doing the following:

Suppose I have a dict k:

>>> k = {\'A\': 68, \'B\': 62, \'         


        

Answer 1

This should do the trick:

>>> k = {'A': 68, 'B': 62, 'C': 47, 'D': 16, 'E': 81}
>>> import random
>>> def weighted_pick(dic):
...     total = sum(dic.itervalues())
...     pick = random.randint(0, total-1)
...     tmp = 0
...     for key, weight in dic.iteritems():
...         tmp += weight
...         if pick < tmp:
...             return key