How can I get a weighted random pick from Python's Counter class?

Question

I have a program where I\'m keeping track of the success of various things using collections.Counter — each success of a thing increments the corr

Answer 1

You can do this rather easily by using itertools.islice to get the Nth item of an iterable:

>>> import random
>>> import itertools
>>> import collections
>>> c = collections.Counter({'a': 2, 'b': 1})
>>> i = random.randrange(sum(c.values()))
>>> next(itertools.islice(c.elements(), i, None))
'a'