How do I perform query filtering in django templates


Question

I need to perform a filtered query from within a django template, to get a set of objects equivalent to python code within a view:

queryset = Modelclass.objects.filter(somekey=foo)

In my template I would like to do

{% for object in data.somekey_set.FILTER %}

but I just can't seem to find out how to write FILTER.

1
73
9/8/2013 12:01:23 AM

Accepted Answer

You can't do this, which is by design. The Django framework authors intended a strict separation of presentation code from data logic. Filtering models is data logic, and outputting HTML is presentation logic.

So you have several options. The easiest is to do the filtering, then pass the result to render_to_response. Or you could write a method in your model so that you can say {% for object in data.filtered_set %}. Finally, you could write your own template tag, although in this specific case I would advise against that.

112
10/22/2008 12:00:27 AM

I just add an extra template tag like this:

@register.filter
def in_category(things, category):
    return things.filter(category=category)

Then I can do:

{% for category in categories %}
  {% for thing in things|in_category:category %}
    {{ thing }}
  {% endfor %}
{% endfor %}

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