Request for feedback on my first Python program

[Cliff Wells]

On Thu, 2003-05-29 at 23:14, Scott Meyers wrote:
> I'm a C++ programmer who's writing his very first Python program.  This
> means the program is going to be gross, and I apologize for that in
> advance.  I don't really have anybody I can show it to for feedback, so I'm
> hoping I can get some comments here.  If there is a better place for me to
> seek guidance, please let me know.

Welcome.  There is no better place.

> The program is supposed to read a file containing directory and file names,
> one per line.  (The file can also contain comment and blank lines, which
> should be ignored.)  For each file or directory name, the program should
> print out whether it's a directory, a file, or neither.  That's it.

Not too bad for a first shot, but for something this simple, I don't
think I'd bother having a function to parse the data:


import sys
import os
  
# Error status codes
returnCodes = {
    'Bad Invocation': 1,
    }


# ----------------------------------------------------------------------
def usage(programName):
    print "Usage: " + os.path.basename(programName) + " [file]"
    sys.exit(returnCodes['Bad Invocation'])


# ----------------------------------------------------------------------
if __name__ == '__main__':
    if len(sys.argv) != 2:
        usage(sys.argv[0])

    for line in open(sys.argv[1], 'r'):
        line = line.strip()
        if line[0] == '#':
            continue
        print line, "is a",
        if os.path.isdir(line):
            print "directory"
        elif os.path.isfile(line):
            print "file"
        else:
            print "non-directory and non-file"


Regards,
Cliff