django - list of lists in template

问题

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?

回答1:

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

回答2:

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

回答3:

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>

来源：https://stackoverflow.com/questions/15703945/django-list-of-lists-in-template