[EMAIL PROTECTED] wrote: >> How could it not be an exception, in the plain English sense of the >> word? Most certainly you're asking for the index because you want to do >> something with the index. If the item is not found, you have no index, >> so that's a special case that must be handled separately. There is no >> logical difference between handling that special case in an except >> clause versus handling it with an if-branch. > > In my case of have done os.listdir() on two directories. I want to see > what files are in directory A that are not in directory B. > I have used exceptions in other languages and only do so on logic that > should never happen. In this case it is known that some of the files > will not be in both lists. I just want to know which ones. > And, as is so often the case, once the *real* problem is stated a more elegant solution become available - in this case, using sets.
afiles = set(os.listdir(dira)) bfiles = set(os.listdir(dirb)) for f in (afiles - bfiles): print "Not common:", f You can also generate the files that are in one directory but ot the other with (afiles | bfiles) - (afiles & bfiles) regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 Holden Web LLC/Ltd http://www.holdenweb.com Skype: holdenweb http://del.icio.us/steve.holden --------------- Asciimercial ------------------ Get on the web: Blog, lens and tag the Internet Many services currently offer free registration ----------- Thank You for Reading ------------- -- http://mail.python.org/mailman/listinfo/python-list
