How to get the difference of two querysets in Django?

Question

I have to querysets. alllists and subscriptionlists

alllists = List.objects.filter(datamode = \'A\')
subscriptionlists = Membership.objects.filter(member__id         


        

Answer 1

How about:

subscriptionlists = Membership.objects.filter(member__id=memberid, datamode='A')
unsubscriptionlists = Membership.objects.exclude(member__id=memberid, datamode='A')

The unsubscriptionlists should be the inverse of subscription lists.

Brian's answer will work as well, though set() will most likely evaluate the query and will take a performance hit in evaluating both sets into memory. This method will keep the lazy initialization until you need the data.