[django]按小时分组统计数据

class Foobar(models.Model):
    name = models.CharField(max_length=100)
    date_created = models.DateField(auto_now_add=True)

    def __unicode__(self):
        return self.name

from collections import defaultdict
from django.db import connection
from django.db.models import Count

select = {'hour': connection.ops.date_trunc_sql('hour', 'date_created')}
result = Foobar.objects.extra(select=select).values('hour').annotate(number=Count('id'))
# [{'number': 10, 'hour': datetime.datetime(2013, 9, 28, 19, 0, 0},
#  {'number': 12, 'hour': datetime.datetime(2013, 9, 29, 19, 0, 0}]

result_new = []
for x in result:
    date = x['hour']
    for y in result_new:
        if y['hour'].hour == date.hour:
            d = y
            break
    else:
        d = defaultdict(int)
        d['hour'] = date
        result_new.append(d)
    d['number'] += x.get('number', 0)
result_new = sorted(result_new, key=lambda x: x['hour'].hour)
# [{'number': 22, 'hour': datetime.datetime(2013, 9, 28, 19, 0, 0},