Django templating: extend a block in same template? - django

Question

So here is the set up (simplified for here):
In my template file I have two sections I would like to add content too by looping of a list of dictionaries, e.g.:
<div class="stuff-a"></div>
<div class="stuff-b"></div>
{% for thing in list %}
<!-- goes into div a -->
<!-- goes into div b -->
{% endfor %}
I thought this would work:
<div class="stuff-a">
{% block diva %}{% endblock %}
</div>
<div class="stuff-b">
{% block divb %}{% endblock %}
</div>
{% for thing in list %}
{% block diva %} thing.stuff_for_div_a {% endblock %}
{% block divb %} thing.stuff_for_div_b {% endblock %}
{% endfor %}
and then django complains about me using each block more than once - shame on me.
Now the solution to this (keeping the same schema) is to make an intermediate template file and then extend it.
My question is, is there a way to append to different specific areas in a django template without having to loop through a list twice or an intermediate template file?
This matters if the loop is somewhat complicated and you dont want to have to update two loops whenever you make a change.
When might this occur in practice (outside this example)? If you have a list where each element in a list references another list (e.g. the way bootstrap handles tabnation)

Answer 1

Now the solution to this (keeping the same schema) is to make an intermediate template file and then extend it.
You can't do this either because you can't use {% block %} in a loop for the same reason as you can't have a block more than once in the same template.
My question is, is there a way to append to different specific areas in a django template without having to loop through a list twice or an intermediate template file?
No you can't. And if ever you could do what you are trying to achieve, it would necessarily involve looping twice over the list behind the scenes.
This matters if the loop is somewhat complicated and you dont want to have to update two loops whenever you make a change.
It matters indeed if the loop is a generator where the next element is calculated at each iteration. But in this case you wouldn't be able to loop twice over the iterable anyway, which is necessary.
If it is a list already calculated and stored in memory, it doesn't matter.
When might this occur in practice (outside this example)? If you have a list where each element in a list references another list (e.g. the way bootstrap handles tabnation)
I don't see how this would be complicated.