[Tutor] Python Error Message

[Nirel Leitman]

Thank you.  And yes, degrees.py is also a folder name along with small.  I was told that file names should have .py at the end of it so that Python can recognize it.  

I went ahead and changed the folder back to just degrees before receiving this email.  I will try again tomorrow with the forward slashing to see if that helps at all.  Also, how to do I create a directory for the small folder?

Thank you again.

> On Jan 26, 2021, at 5:48 PM, Alan Gauld via Tutor <tutor at python.org> wrote:
> 
> I'm forwarding to the list so others can comment....
> 
> 
> I've loaded and run your file and (once I mock up unit.py_)
> it works with no errors until it tries to load data.
> So I'm not seeing the error you are getting which suggests
> its an environment issue.
> 
> However, looking back at your original post I noticed
> something odd that I missed first time:
> 
> C:\Users\leitm>python C:\Users\leitm\Desktop\AI\degrees.py
> "C:\Users\leitm\Desktop\AI\degrees.py\small"
> 
> The argument to degrees.py is a path string.
> 
> But the last element of the path is a filename followed
> by \small - is that correct?
> 
> Your code is looking for a directory!
> 
> I don't think that would cause the missing main module
> error but you should probably fix it!
> 
> The other issue there is that I'm not sure how windows
> python will handle that path string with the backslashes.
> You may need to escape them or use forward slashes(which
> Windows can process with no problems inside a string)
> 
> Alan G.
> 
> 
> 
> 
> 
>> On 27/01/2021 01:42, Alan Gauld via Tutor wrote:
>> 
>>> 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
> 
> 
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
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