Request for feedback on my first Python program

[Bernard Delmée]

>   # if this language had a main(), it'd be here...

In python, the customary idiom would be:

if __name__ == '__main__':
    # main script or call to function

This way your script works both standalone and as a module if needed.

> Aside from being ugly (how do I get rid of the newline that follows
> each directory or file name?), the problem is that the first entry IS
> a directory and the second one IS a file.  So clearly I'm doing
> something wrong.  Any idea what it is?

As shown in your output, the newlines are what cause the "ugly" *and*
wrong result. Every line returned by readlines() ends with a NL which
you need to strip before accessing/testing the file it represents.

So insted of
>   for i in lines:
>        # ...
You could say
    for l in lines:
        i = l.strip()
        # ...

Now, when can we expect "effective python" ?-)
But then python does not nearly have the pitfalls and idiosyncrasies
of C++, which one can only truly comprehend after reading your very
fine books. Thanks for these.

Regards,

Bernard.