Re: Best use of "open" context manager

On 07Jul2024 22:22, Rob Cliffe <rob.cliffe@btinternet.com> wrote:

Remember, the `open()` call returns a file object _which can be used as a context manager_. It is separate from the `with` itself.

Did you test this?
    f = open(FileName) as f:
is not legal syntax.

No. You're right, remove the "as f:".

it's legal, but doesn't work (trying to access the file after "with f" raises the same
    ValueError: I/O operation on closed file.

This astounds me. Code snippet to demo this?
Here's a test script which I've just run now:
     FileName = 'foo.txt'
     try:
       f = open(FileName)
     except FileNotFoundError:
       print(f"File {FileName} not found")
       sys.exit()
     with f:
       for line in f:
         print("line:", line.rstrip())
Here's the foo.txt file:
     here are
     some lines of text
Here's the run:
     % python3 p.py
     line: here are
     line: some lines of text