On Thu, Feb 10, 2011 at 2:29 PM, Alex Robbins
<alexander.j.robb...@gmail.com> wrote:
> Yeah, you'll definitely want to find some aggregate to do the sorting.

Ok, didn't know it. I'll take a look at it...

> The only way to sort by a custom method is doing an in-python sort,
> which is going to be much slower than having the db sort for you.

Yeah, I tought so but it seems (to me) the only way of doing this...

>  If you post the score models, we could probably help more.

The score models are from django-voting:

http://django-voting.googlecode.com/svn/trunk/voting/models.py
http://django-voting.googlecode.com/svn/trunk/voting/managers.py

Thanks for the help!

Andres


>
> Alex
>
> On Feb 9, 8:49 am, "Casey S. Greene" <csgre...@princeton.edu> wrote:
>> I haven't used django-voting but it sounds to me like you want something
>> like:
>> Link.objects.aggregate(Avg(score = 'vote__score')).order_by('score')
>>
>> If I recall correctly you can chain aggregate and order_by.
>>
>> Anyway, that example and this link should get you started at 
>> least:http://docs.djangoproject.com/en/dev/topics/db/aggregation/
>>
>> Hope this helps!
>> Casey
>>
>>
>>
>>
>>
>>
>>
>> On Wed, 2011-02-09 at 10:08 +0100, Andres Lucena wrote:
>> > On Tue, Feb 8, 2011 at 6:00 PM, Andres Lucena <andresluc...@gmail.com> 
>> > wrote:
>> > > Dear Gurus,
>>
>> > > I've made a custom method for getting the score (from django-voting)
>> > > for a giving Model:
>>
>> > > class Link(models.Model):
>> > >    episode = models.ForeignKey("Episode", related_name="links")
>> > >    url = models.CharField(max_length=255, unique=True, db_index=True)
>>
>> > >    def __unicode__(self):
>> > >        return self.url
>>
>> > >    def get_score(self):
>> > >        return Vote.objects.get_score(self)['score']
>>
>> > > Now I want to make a custom manager to getting the top-scored links
>> > > for the given episode. AFAIK, you can't sort by a custom method, so
>> > > I'm trying to apply the ordering through sorted(), like this links
>> > > says:
>>
>> > >http://stackoverflow.com/questions/981375/using-a-django-custom-model...
>> > >http://stackoverflow.com/questions/883575/custom-ordering-in-django
>>
>> > > So, what I have now is this:
>>
>> > > class LinkGetTopScores(models.Manager):
>> > >    def get_top_score(self):
>> > >        return sorted(self.filter(episode=self.episode), key=lambda n:
>> > > n.get_score)
>>
>> > > class Link(models.Model):
>> > >    episode = models.ForeignKey("Episode", related_name="links")
>> > >    url = models.CharField(max_length=255, unique=True, db_index=True)
>> > >    get_top_score = LinkGetTopScores()
>> > > ....
>>
>> > > So of course this isn't working because of the self.episode stuff...
>> > > But I've to filter somehow by episode (the ForeignKey), and I don't
>> > > know how. Is there anyway of doing this?? What I'm doing is right or
>> > > there would be an easier way of doing this?
>>
>> > I noticed that the .filter isn't necesary, so now I have this:
>>
>> > class LinkGetTopScores(models.Manager):
>> >     def get_top_score(self):
>> >         return sorted(self.all(), key=lambda n: n.get_score)
>>
>> > But it don't sort by score, and I don't know what I'm doing wrong :S
>>
>> > Any idea?
>>
>> > Thanks,
>> > Andres
>>
>> > > Thank you,
>> > > Andres
>
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