Random Python dictionary key, weighted by values

Question

I have a dictionary where each key has a list of variable length, eg:

d = {
 \'a\': [1, 3, 2],
 \'b\': [6],
 \'c\': [0, 0]
}

Is there a cle

Answer 1

Without constructing a new, possibly big list with repeated values:

def select_weighted(d):
   offset = random.randint(0, sum(d.itervalues())-1)
   for k, v in d.iteritems():
      if offset < v:
         return k
      offset -= v