Max, Just wanted to thank you for responding to my question. You are correct that the list comprehension is pythonic, though I was ideally looking for a efficient method from a database perspective.
Thanks, Brian On Apr 12, 2006, at 2:16 AM, Max Battcher wrote: > > Russell Cloran wrote: >> Hi, >> >> On Tue, 2006-04-11 at 21:20 -0400, Max Battcher wrote: >>> if sometag.article_set.count() == 0: >>> pass # your code here >> >> This will test if one tag has an empty article_set. AFAICT, the >> question >> is on how to find all tags which have an empty article_set. Yes, you >> could do it this way, but it means querying the DB again for every >> tag. > > Oh, right. You could do: > > tags = [tag for tag in Tag.objects.all() if tag.article_set.count() > == 0] > > n queries for n tags, but it is "pretty" Python. Doing db-cleanup > shouldn't happen all that often, so you probably don't need the best > performance, and I'd just stick with the list comprehension. > > Too bad there isn't some cool easy Python way to make a list > comprehension/generators like that as Lazy as the Descriptors... > Byte-code parsing, anyone? > > http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/442447 > > -- > --Max Battcher-- > http://www.worldmaker.net/ > "I'm gonna win, trust in me / I have come to save this world / and in > the end I'll get the grrrl!" --Machinae Supremacy, Hero (Promo Track) > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users -~----------~----~----~----~------~----~------~--~---
