Django aggregation get_*_display function usage
This question relates to Django Aggregation/Annotation in 1.1. Suppose I have a simple model with an IntegerField that has a "choices" parameter passed to it. In this case, it maps to a GENDERS tuple as shown. Normally, in a template (or view) I can refer to the textual value of the gender by using the get_gender_display() function.
However, when I annotate the gender counts as I do in the view below, I can't then lookup the textual value for each gender using the get_gender_display() function. See the template excerpt below. How would I go about getting the textual valu开发者_StackOverflow社区e for gender back?
I've never used Django Aggregation before, so maybe I'm missing an obvious solution. Thank you for considering my situation.
models.py
GENDERS = (
('',' '),
(1,'Female'),
(2,'Male'),
)
class Subscriber(models.Model):
gender = models.IntegerField(blank=True, null=True, choices=GENDERS)
views.py
from django.db.models import Count
def myview(request):
...
sum_gender = Subscriber.objects.values('gender').annotate(gender_sum=Count('gender'))
context = { 'sum_gender':sum_gender, }
return render_to_response(template_name, context,context_instance=RequestContext(request))
template
...
{% for genderAndsum in sum_genders %}
<div>{{ genderAndsum.get_gender_display }} {{ genderAndsum.gender_sum }}</div>
{% endfor %}
...
The problem is not the aggregation, it's that you're using values()
. This returns a ValuesQuerySet, each of whose entries is a dictionary - not a Subscriber object. Obviously, that dict doesn't have any get_FOO_display
methods.
The quickest solution would be to use a custom filter:
from myapp.models import GENDERS
@register.filter
def gender_lookup(value)
gender_dict = dict(GENDERS)
return gender_dict.get(value, '')
and in the template:
<div>{{ genderAndsum.gender|gender_lookup }} {{ genderAndsum.gender_sum }}</div>
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