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 clean way to get a random dictionary key, weighted by the length of its value? random.choice(d.keys()) will weight the keys equally, but in the case above I want 'a' to be returned roughly half the time.

Answer 1

This would work:

random.choice([k for k in d for x in d[k]])