[Tutor] Still not understanding passing filenames in Python

[boB Stepp]

Now in "3.4 Modules" at
https://dabeaz-course.github.io/practical-python/Notes/03_Program_organization/04_Modules.html

Earlier in the course I wrote a program, report.py, that runs as so:

bob at Dream-Machine1:~/practical-python/Work$ python3 report.py

Enter path to portfolio file:  Data/portfolio.csv
Enter path to stock prices file:  Data/prices.csv

       Name     Shares      Price     Change 
---------- ---------- ---------- ---------- 
         AA        100      $9.22     -22.98
        IBM         50    $106.28      15.18
        CAT        150     $35.46     -47.98
       MSFT        200     $20.89     -30.34
         GE         95     $13.48     -26.89
       MSFT         50     $20.89     -44.21
        IBM        100    $106.28      35.84

Current portfolio value = $28,686.10
Current portfolio gain/loss = $-15,985.05

In "Exercise 3.12: Using your library module" Beazley has us importing the
recently discussed fileparse module containing the parse_csv() function to
replace the code previously written in the read_portfolio() function in
report.py.  So I added "import fileparse" and modified the read_portfolio()
function to:

def read_portfolio(filename: str) -> List[Dict[str, Union[str, int, float]]]:
     """Read a file and return a portfolio list of records."""
     portfolio = fileparse.parse_csv(
         filename, select=["name", "shares", "price"], types=[str, int, float]
     )
     return portfolio

report.py and fileparse.py are both in the same Work directory.  Data is a
subdirectory of Work.

But when I try to run this program with the same file location entries
I get:

bob at Dream-Machine1:~/practical-python/Work$ python3 report.py

Enter path to portfolio file:  Data/porfolio.csv
Enter path to stock prices file:  Data/prices.csv
Traceback (most recent call last):
   File "report.py", line 113, in <module>
     main()
   File "report.py", line 104, in main
     portfolio = read_portfolio(portfolio_path)
   File "report.py", line 18, in read_portfolio
     filename, select=["name", "shares", "price"], types=[str, int, float]
   File "/home/bob/practical-python/Work/fileparse.py", line 25, in parse_csv
     with open(filename) as fileobj:
FileNotFoundError: [Errno 2] No such file or directory: 'Data/porfolio.csv'

If I use absolute file paths, "/home/bob/practical-python..." it works.

If I use "./Data/portfolio.csv" and "./Data/prices.csv" it works.  I
currently do not understand the differences.  Obviously I do understand one
or more things.  A helpful explanation please?  Thanks!

-- 
Wishing you only the best,

boB Stepp