another python style question -- copying a data file

Guy Middleton guy at obstruction.com
Tue Apr 22 20:45:52 CEST 2003


In article <mailman.1051033654.17248.python-list at python.org>,
=?ISO-8859-1?Q?Gerhard_H=E4ring?=  <gh at ghaering.de> wrote:
> Guy Middleton wrote:
> > Ok, here's another style question.
> > 
> > I want to copy a data file, but if the file doesn't already exist, I don't
> > care.  I do care about any other errors, such as wrong permissions.
> > 
> > I have the following code, is this a typical Python way to do this?
> > 
> >     try:
> >         os.stat(DATAFILE)
> >         os.system("cp %s %s.new" % (DATAFILE, DATAFILE))
> >     except OSError, arg:
> >         # ENOENT is ok, we didn't do the copy
> >         # anything else is a problem
> >         if arg.errno != errno.ENOENT:
> >             raise
> 
> Here's what I'd do:
> 
> if os.path.exists(DATAFILE):
>      shutil.copyfile(DATAFILE, "%s.new" % DATAFILE)

Aha, I didn't know about shutil.  This is obviously better.  :-)




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