[Tutor] Python Error Message

[Alan Gauld]

On 26/01/2021 17:18, Nirel Leitman wrote:
> Here is the main code for degrees.py -- it is very long:
>
> import csv
> import sys
> from util import Node, StackFrontier, QueueFrontier
> # Maps names to a set of corresponding person_ids
> names = {}
> # Maps person_ids to a dictionary of: name, birth, movies (a set of movie_ids)
> people = {}
> # Maps movie_ids to a dictionary of: title, year, stars (a set of person_ids)
> movies = {}
> def load_data(directory):
>     """
>     Load data from CSV files into memory.
>     """
>     # Load people
>     with open(f"{directory}/people.csv", encoding="utf-8") as f:
>         reader = csv.DictReader(f)
>         for row in reader:
>             people[row["id"]] = {
>                 "name": row["name"],
>                 "birth": row["birth"],
>                 "movies": set()
>             }
>             if row["name"].lower() not in names:
>                 names[row["name"].lower()] = {row["id"]}
>             else:
>                 names[row["name"].lower()].add(row["id"])
>     # Load movies
>     with open(f"{directory}/movies.csv", encoding="utf-8") as f:
>         reader = csv.DictReader(f)
>         for row in reader:
>             movies[row["id"]] = {
>                 "title": row["title"],
>                 "year": row["year"],
>                 "stars": set()
>             }
>     # Load stars
>     with open(f"{directory}/stars.csv", encoding="utf-8") as f:
>         reader = csv.DictReader(f)
>         for row in reader:
>             try:
>                 people[row["person_id"]]["movies"].add(row["movie_id"])
>                 movies[row["movie_id"]]["stars"].add(row["person_id"])
>             except KeyError:
>                 pass
> def main():
>     if len(sys.argv) > 2:
>         sys.exit("Usage: python degrees.py [directory]")
>     directory = sys.argv[1] if len(sys.argv) == 2 else "large"
>     # Load data from files into memory
>     print("Loading data...")
>     load_data(directory)
>     print("Data loaded.")
>     source = person_id_for_name(input("Name: "))
>     if source is None:
>         sys.exit("Person not found.")
>     target = person_id_for_name(input("Name: "))
>     if target is None:
>         sys.exit("Person not found.")
>     path = shortest_path(source, target)
>     if path is None:
>         print("Not connected.")
>     else:
>         degrees = len(path)
>         print(f"{degrees} degrees of separation.")
>         path = [(None, source)] + path
>         for i in range(degrees):
>             person1 = people[path[i][1]]["name"]
>             person2 = people[path[i + 1][1]]["name"]
>             movie = movies[path[i + 1][0]]["title"]
>             print(f"{i + 1}: {person1} and {person2} starred in {movie}")
> def shortest_path(source, target):
>     """
>     Returns the shortest list of (movie_id, person_id) pairs
>     that connect the source to the target.
>     If no possible path, returns None.
>     """
>     # TODO
>     raise NotImplementedError
> def person_id_for_name(name):
>     """
>     Returns the IMDB id for a person's name,
>     resolving ambiguities as needed.
>     """
>     person_ids = list(names.get(name.lower(), set()))
>     if len(person_ids) == 0:
>         return None
>     elif len(person_ids) > 1:
>         print(f"Which '{name}'?")
>         for person_id in person_ids:
>             person = people[person_id]
>             name = person["name"]
>             birth = person["birth"]
>             print(f"ID: {person_id}, Name: {name}, Birth: {birth}")
>         try:
>             person_id = input("Intended Person ID: ")
>             if person_id in person_ids:
>                 return person_id
>         except ValueError:
>             pass
>         return None
>     else:
>         return person_ids[0]
> def neighbors_for_person(person_id):
>     """
>     Returns (movie_id, person_id) pairs for people
>     who starred with a given person.
>     """
>     movie_ids = people[person_id]["movies"]
>     neighbors = set()
>     for movie_id in movie_ids:
>         for person_id in movies[movie_id]["stars"]:
>             neighbors.add((movie_id, person_id))
>     return neighbors
> if __name__ == "__main__":
>     main()
>
> Please let me know how I can proceed from here.  Thank you again for
> your assistance.
>
> - Nirel
>
> On Monday, January 25, 2021, 06:04:41 PM MST, Alan Gauld via Tutor
> <tutor at python.org> wrote:
>
>
> On 25/01/2021 20:24, Nirel Leitman via Tutor wrote:
> > I keep getting this error message:
> > C:\Users\leitm>python C:\Users\leitm\Desktop\AI\degrees.py
> "C:\Users\leitm\Desktop\AI\degrees.py\small">
> C:\Users\leitm\AppData\Local\Programs\Python\Python39\python.exe:
>
> The error says:
> > can't find '__main__' module in
> 'C:\\Users\\leitm\\Desktop\\AI\\degrees.py'
>
> > Why can't my computer find my folder?
>
> It evidently can, it is a main module that it says is missing not
> that it can't find the file. It's looking in the file for main
> and not finding it.
>
> >   What do I need to change for my computer to read this?
>
> It depends on what is in the file.
> Can you show us the main code for degrees.py?
>
>
> -- 
> Alan G
> Author of the Learn to Program web site
> http://www.alan-g.me.uk/
> http://www.amazon.com/author/alan_gauld
> Follow my photo-blog on Flickr at:
> http://www.flickr.com/photos/alangauldphotos
>
>
>
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-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
Follow my photo-blog on Flickr at:
http://www.flickr.com/photos/alangauldphotos