#26141: __lt__ for model instances
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Reporter: srkunze | Owner: nobody
Type: New feature | Status: new
Component: Database layer (models, ORM) | Version: master
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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We need to sort a list of model instances (not a queryset).
After some research, we didn't find a standard way to do this with Django
model instances. Would it be possible to implement {{{__lt__}}} for model
instances via the meta class mechanism?
Currently, we write a wrapper where we implemented the following
{{{__lt__}}} method:
{{{
def __lt__(self, other):
for criteria in self.object._meta.ordering:
field = criteria[1:] if criteria.startswith('-') else criteria
mine = getattr(self.object, field)
theirs = getattr(other.object, field)
if isinstance(mine, unicode):
mine = locale.strxfrm(mine.encode('utf8'))
theirs = locale.strxfrm(theirs.encode('utf8'))
if mine == theirs:
continue
if criteria.startswith('-'):
return mine > theirs
return mine < theirs
raise NotImplementedError
}}}
Please note, that the implementation is locale-aware.
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Ticket URL: <https://code.djangoproject.com/ticket/26141>
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