count_number_of_friends

count_number_of_friends.py

    def count_number_of_friends(self, key, values):
        '''
        Count the number of mutual friends.

        Input ({[friend1, friend2], [-1, -1]};
               {[friend1, friend2],[1, 1]};):

            ["jonas", "marcel"] -1
            ["marcel", "maria"] -1
            ["jose", "marcel"]  -1
            ["amanda", "marcel"]    -1
            ["fabio", "marcel"] 1
            ["fabiola", "marcel"]   1
            ["carol", "marcel"] 1
            ["carol", "marcel"] 1


        Output ({[friend1, friend2], numberOfMutualFriends}):

            ["fabio", "marcel"] 1
            ["fabiola", "marcel"]   1
            ["marcel", "patricia"]  1
            ["marcel", "paula"] 1
            ["carol", "marcel"] 2

        '''

        f1, f2 = key
        mutual_friends_count = 0
        for value in values:
            if value == -1:
                return
            mutual_friends_count += value

        yield (f1, f2), mutual_friends_count