Access object value by other object value in template in Django?

Question

This {{ category.id }} returns me 1

This {{ categories_counts.1 }} returns me data

But {{ categories_counts.category.id }} doesn't work?

Is it possible to access value by other object value?

views.py:

categories = Category.objects.all()
categories_counts = {}
for category in categories:
    count = Venue.objects.filter(category_id=category.id).count()
    categories_counts[category.id] = count

So categories containst:

<QuerySet [<Category: restaurants>, <Category: sportfitness>, <Category: carservices>, <Category: beautysalons>]>

categories_counts contains:

{1: 1, 2: 0, 3: 0}

category Model:

class Category(models.Model):
    name = models.CharField(max_length=20)
    bg_name = models.CharField(max_length=20, default=None)
    category_bg_name = models.CharField(max_length=100, default=None)

You need a [custom template tag](https://stackoverflow.com/questions/8000022/django-template-how-to-look-up-a-dictionary-value-with-a-variable) — Sayse, Mar 17 '20 at 15:50
If you show your view and template, there might be another way you can loop through the dictionary, for example `{% for category, count in categories_counts.items %}{{ category }}{{ count }}{% endfor %}`. — Alasdair, Mar 17 '20 at 16:00
I'm guessing `categories_counts` is a list and there's nothing at `categories_counts['category']` so that's why it doesn't work. — Tim Tisdall, Mar 17 '20 at 16:08

Alasdair · Accepted Answer · 2020-03-19T11:02:56.243

In general, you can't access categories_counts[category.id] in the Django template unless you create a custom template tag, as @sayse says in the comments.

In your specific case, you can annotate the queryset with the venue counts.

from django.db.models import Count
categories = Category.objects.annotate(num_venues=Count('venue'))

Then in your template you can do something like:

{% for category in categories %}
{{ category.name }} has {{ category.num_venues }} venue(s)
{% endfor %}

Access object value by other object value in template in Django?

1 Answers1