Forum Archive

My program was creating extra ‘-‘ characters, I spent ages looking in other parts of the code for the extra character creator.

The lesson “ Don’t make stupid mistakes inside ‘try:’ code

Like this one

try:
    with open(self.fp_files[hd], 'r')   as f: # fp_files loaded in setup
        self.fastestplayers.append(f.read())
        print('during opening', hd, self.fastestplayers(hd))
except:
    self.fastestplayers.append('-')

The stupid thing was I forgot I had added the print command to follow the logic.
Hence I didn’t miss it!

Of course the () rather than [] in the superfluous print line created an error that triggered the exception code.

Hence the extra ‘-‘

Shared to help others look more carefully for stupid mistakes inside “try” code, after all you have told the interpreter you will handle errors in there!
...

Another lesson might be to avoid the try/except anti pattern.

If you had caught only the errors that could be thrown by open or read

except (IOError, OSError):

Then errors inside the try that you were not expecting still get raised. Or maybe you want to catch only FileNotFoundError, but you get the idea -- catch only the errors you expect can happen.

Agreed. The anitpattern is the bare except: https://realpython.com/the-most-diabolical-python-antipattern/

Thanks guys for the specific pointer, ‘catch just the exception you WANT to catch”

AND THE GREAT READ, which reinforced the importance of the specific pointer above, as well as fully Logging exception events.

The Doh! lesson is now learnable at a great new depth...

I now only except “FileNotFoundError”