python - Combine elements in list of Tuples? -

i'm working on program takes in imdb text file, , outputs top actors (by movie appearances) based on user input n.

however, i'm running issue i'm having slots taken actors in same amount of movies, need avoid. rather, if 2 actors in 5 movies, example, number 5 should appear , actors names should combined , separated semicolon.

i've tried multiple workarounds , nothing has yet worked. suggestions?

if __name__ == "__main__":     imdb_file = raw_input("enter name of imdb file ==> ").strip()     print imdb_file     n= input('enter number of top individuals ==> ')     print n       actors_to_movies = {}      line in open(imdb_file):         words = line.strip().split('|')         actor = words[0].strip()         movie = words[1].strip()         if not actor in actors_to_movies:             actors_to_movies[actor] = set()         actors_to_movies[actor].add(movie)      movie_list= sorted(list(actors_to_movies[actor]))       #arranges dictionary list of tuples#     d = [ (x, actors_to_movies[x]) x in actors_to_movies]     descending = sorted(d, key = lambda x: len(x[1]), reverse=true)      #prints tuples in descending order n number of times (user input)#     in range(n):         print str(len(descending[i][1]))+':', descending[i][0] 

there useful method itertools.groupby

it allows split list groups key. using can write function prints top actors:

import itertools def print_top_actors(actor_info_list, top=5):     """     :param: actor_info_list should contain tuples of (actor_name, movie_count)     """     actor_info_list.sort(key=lambda x: x[1], reverse=true)     i, (movie_count, actor_iter) in enumerate(itertools.groupby(actor_info_list)):         if >= top:             break         print movie_count, ';'.join(actor actor, movie_count in actor_iter) 

and example of usage:

>>> print_top_actors( ...     [ ...         ("dicaprio", 100500), ...         ("pitt", 100500), ...         ("foo", 10), ...         ("bar", 10), ...         ("baz", 10), ...         ("qux", 3), ...         ("lol", 1) ...     ], top = 3) 100500 dicaprio;pitt 10 foo;bar;baz 3 qux