inverting dictionary in python

Question

I have this dictionary

{'jackie chan': ('rush hour', 'rush hour 2'), 
 'crish tucker': ('rush hour', 'rush    hour 2')}

I want the inverse dictionary to be

{'rush hour': ('jackie chan', 'crish tucker'), 
 'rush hour 2': ('jackie chan', 'crish tucker')}

I already got the function to inverse but it doesn't look like the second dictionary

def invert_actor_dict(actor_dict):
    movie_dict = {}
    for key,value in actor_dict.iteritems():

        for actor in value:
            if actor in movie_dict:
                movie_dict[actor].append(key)
            else:
                movie_dict[actor] = (key)
    return movie_dict

Answer 1

You can easily do this with collections.defaultdict:

def invert_dict(d):
    inverted_dict = collections.defaultdict(set)
    for actor, movies in d.iteritems():
        for movie in movies:
            inverted_dict.add(actor)
    return inverted_dict