django - list of lists in template

Question

I am trying to render a list of lists zipped with zip().

list_of_list = zip(location,rating,images)

I want to render this list_of_list to template and want to show only the first image of each location.

my location and image models are these:

class Location(models.Model):
  locationname = models.CharField

class Image(models.Model):
  of_location = ForeignKey(Location,related_name="locs_image")
  img = models.ImageField(upload_to=".",default='')

here is the zipped list. How can I access only the first image of each location in template?

enter image description here

Just curious, why are you zipping actually? Why not use relationships? — Bibhas Debnath
– Bibhas Debnath, Commented Mar 29, 2013 at 13:46
@Bibhas, you mean: all_locations = Location.objects.all() and in template {% for loc in all_locations %} {% for img in loc.locs_image.all %}{{img.img.name}} {% endfor %} {% endfor %} ? — doniyor
– doniyor, Commented Mar 30, 2013 at 2:37
Yes. Why not that? And if you want just one item, you can use slice tag in templates. — Bibhas Debnath
– Bibhas Debnath, Commented Mar 30, 2013 at 7:06

Sami N · Accepted Answer · 2013-03-29 13:18:03Z

5

Pass the list_of_lists to the RequestContext. Then you can reference the first index of the images list in your template:

{% for location, rating, images in list_of_lists %}

...
<img>{{ images.0 }}</img>
...

{% endfor %}

How to render a context

answered Mar 29, 2013 at 13:18

Sami N

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1 Comment

Sami N Over a year ago

Can you show your render-function and the part of your template that you're targeting?

Ronan Boiteau · Accepted Answer · 2017-12-21 18:14:25Z

1

I think you should have a look at django-multiforloop.

edited Dec 21, 2017 at 18:14

Ronan Boiteau

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answered Mar 29, 2013 at 13:21

dusual

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Comments

j-i-l · Accepted Answer · 2017-11-16 10:57:05Z

You can handle list elements in your template also based on their type (with Django 1.11 ).

So in case you have the view you describe:

# view.py
# ...
list_of_lists = zip(location,rating,images)
context['list_of_lists'] = list_of_lists
# ...

All you need to do is create a tag to determine the type of your elements in the template:

# tags.py
from django import template
register = template.Library()
@register.filter
def get_type(value):
    return type(value).__name__

Then you can detect the content type of a list element and only display the first element if the list element is a list itself:

{% load tags %}
{# ...other things #}
<thead>
  <tr>
    <th>locationname</th>
    <th>rating</th>
    <th>images</th>
  </tr>
</thead>
<tbody>
  <tr>
    {% for a_list in list_of_lists %}
    {% for an_el in a_list %}
    <td>
        {# if it is a list only take the first element #}
        {% if an_el|get_type == 'list' %}
        {{ an_el.0 }}
        {% else %}
        {{ an_el }}
        {% endif %}
    </td>
    {% endfor %}
  </tr>
  % endfor %}
</tbody>

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