I think in this case the Python docs were mis-interpreted. The key point to consider when writing a __hash__ function is that two objects that compare equal must hash equally, and the hash value cannot change. Just because an object is mutable doesn't mean that these rules will be violated. In particular, Django model instances will usually simply use their id attribute as the hash, and so will be perfectly acceptable as dictionary keys.
--Ned. On Feb 14, 10:19 am, Ivan Sagalaev <[EMAIL PROTECTED]> wrote: > David Abrahams wrote: > > I just wrote some code that used Model instances as keys in a dict, > > and was surprised to find two instances in the dict that represented > > the same object in the database. Shouldn't that be impossible? If > > you can't guarantee that a given object in the database is always > > represented by the same Python instance, shouldn't django.db.Model > > have __hash__ and __eq__ methods that makes equivalent instances hash > > the same? > > This is a known issue:http://code.djangoproject.com/ticket/2936 > > The ticket was closed as "invalid" with a good reason (model instances > are mutable and shouldn't be used as keys in dicts). --~--~---------~--~----~------------~-------~--~----~ 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?hl=en -~----------~----~----~----~------~----~------~--~---
