Think Python - Denison University

144 Chapter 14. FilesExercise 14.7 The Internet Movie Database (IMDb) is an online collection of information aboutmovies. Theirdatabaseisavailableinplaintextformat,soitisreasonablyeasytoreadfromPython.Forthisexercise,thefilesyouneedareactors.list.gzandactresses.list.gz;youcandownloadthem fromwww.imdb.com/interfaces#plain.I have written a program that parses these files and splits them into actor names, movie titles, etc.You can download itfromthinkpython.com/code/imdb.py.If you run imdb.py as a script, it reads actors.list.gz and prints one actor-movie pair per line.Or, if you import imdb you can use the function process_file to, well, process the file. Thearguments are a filename, a function object and an optional number of lines to process. Here is anexample:import imdbdef print_info(actor, date, title, role):print actor, date, title, roleimdb.process_file('actors.list.gz', print_info)When you call process_file, it opens filename, reads the contents, and calls print_info oncefor each line in the file. print_info takes an actor, date, movie title and role as arguments andprintsthem.1. Write a program that reads actors.list.gz and actresses.list.gz and uses shelve tobuild adatabase that maps fromeach actor toalistof his orher films.2. Twoactorsare“costars”iftheyhavebeeninatleastonemovietogether. Processthedatabaseyou built in the previous step and build a second database that maps from each actor to a listof his or her costars.3. Write a program that can play the “Six Degrees of Kevin Bacon,” which you can read aboutat wikipedia.org/wiki/Six_Degrees_of_Kevin_Bacon. This problem is challenging becauseit requires you to find the shortest path in a graph. You can read about shortest pathalgorithms atwikipedia.org/wiki/Shortest_path_problem.