Appending all other key:values in a specific dictionary in Python

Question

I am trying to create a list of all actors' co-actors. The exemplary input looks like this:

cast_info = [[
  {'name': 'Drew Barrymore'},
  {'name': 'Brian Herzlinger'},
  {'name': 'Corey Feldman'},
  {'name': 'Eric Roberts'}, {'name': 'Griffin Dunne'}, {'name': 'Samuel L. Jackson'}, {'name': 'Matt LeBlanc'}, {'name': "Bill D'Elia"}], [{'name': 'Erich Anderson'}, {'name': 'Judie Aronson'}, {'name': 'Peter Barton'}, {'name': 'Kimberly Beck'}, {'name': 'Tom Everett'}, {'name': 'Flashlight Man'}, {'name': 'Corey Feldman'}]]

and the expected output can have the following structure:

{'Drew Barrymore': ['Brian Herzlinger', 'Corey Feldman', 'Eric Roberts', 'Griffin Dunne', 'Samuel L. Jackson', 'Matt LeBlanc', "Bill D'Elia"],
 'Brian Herzlinger': ['Drew Barrymore', 'Corey Feldman', 'Eric Roberts', 'Griffin Dunne', 'Samuel L. Jackson', 'Matt LeBlanc', "Bill D'Elia"],
 'Corey Feldman': ['Drew Barrymore', 'Brian Herzlinger', 'Eric Roberts', 'Griffin Dunne', 'Samuel L. Jackson', 'Matt LeBlanc', "Bill D'Elia", 'Erich Anderson', 'Judie Aronson', 'Peter Barton', 'Kimberly Beck', 'Tom Everett', 'Flashlight Man'],
 'Eric Roberts': ['Drew Barrymore', 'Brian Herzlinger', 'Corey Feldman', 'Griffin Dunne', 'Samuel L. Jackson', 'Matt LeBlanc', "Bill D'Elia"],
 'Griffin Dunne': ['Drew Barrymore', 'Brian Herzlinger', 'Corey Feldman', 'Eric Roberts', 'Samuel L. Jackson', 'Matt LeBlanc', "Bill D'Elia"],
 'Samuel L. Jackson': ['Drew Barrymore', 'Brian Herzlinger', 'Corey Feldman', 'Eric Roberts', 'Griffin Dunne', 'Matt LeBlanc', "Bill D'Elia"],
 'Matt LeBlanc': ['Drew Barrymore', 'Brian Herzlinger', 'Corey Feldman', 'Eric Roberts', 'Griffin Dunne', 'Samuel L. Jackson', "Bill D'Elia"],
 "Bill D'Elia": ['Drew Barrymore', 'Brian Herzlinger', 'Corey Feldman', 'Eric Roberts', 'Griffin Dunne', 'Samuel L. Jackson', 'Matt LeBlanc'],
 'Erich Anderson': ['Judie Aronson', 'Peter Barton', 'Kimberly Beck', 'Tom Everett', 'Flashlight Man', 'Corey Feldman'],
 'Judie Aronson': ['Erich Anderson', 'Peter Barton', 'Kimberly Beck', 'Tom Everett', 'Flashlight Man', 'Corey Feldman'],
 'Peter Barton': ['Erich Anderson', 'Judie Aronson', 'Kimberly Beck', 'Tom Everett', 'Flashlight Man', 'Corey Feldman'],
 'Kimberly Beck': ['Erich Anderson', 'Judie Aronson', 'Peter Barton', 'Tom Everett', 'Flashlight Man', 'Corey Feldman'],
 'Tom Everett': ['Erich Anderson', 'Judie Aronson', 'Peter Barton', 'Kimberly Beck', 'Flashlight Man', 'Corey Feldman'],
 'Flashlight Man': ['Erich Anderson', 'Judie Aronson', 'Peter Barton', 'Kimberly Beck', 'Tom Everett', 'Corey Feldman']}

Note that the actor Corey Feldman will have costars from both movies.

What I tried so far

This is the closest I have gotten. It gives me the first actor's name in list_of_actors, repeated in a list 10 times. He appears in 10 films so it is looping through the film_cast properly.

I have the second last line of code because I only want the co-stars to appear once, if the same 2 actors star in 2 different films together they will still only be on each others list once.

for film_cast in cast_info:
    for actor in film_cast:
        if list_of_actors[0] in actor['name']:
            actor_name2 = actor['name'] 
            actor_name2 != list_of_actors[0]
            costars_lists[0].append(actor_name2) 

One of my problems with this approach is the definition of actor_name2. I have defined actor_name the same way as actor_name2 in different code.

I'm not sure why my end list contains the first actor repeated 10 times as I am not appending list_of_actor[0], I'm trying to append the actor_name2.

I want to check if an actor is in a film_cast. If they are, check if all other actors are in a corresponding list, append the actors that aren't in the list already. Perform this for each film_cast in cast_info. Perform this for each actor in list_of_actors.

Answer 1

An O(N^2) soultion is to iterate over film cast and each actor to append film cast to an actor to co-stars mapping.

costars_dict = {}
for film_cast in cast_info:
    for actor in film_cast:
        costars = [cs['name'] for cs in film_cast if cs['name'] != actor['name']]
        if actor['name'] in costars_dict:
            costars_dict[actor['name']] += costars
        else:
            costars_dict[actor['name']] = costars