How to assemble a variable name in Django templating language?

Question

I am trying to assemble a variable in Django template in that way:
obj.length.forloop.counter where the foorloop.counter should return the number.
for example obj.length.1 then obj.length.2 and so on...

I tried the add filter: obj.length|add:forloop.counter but that returned nothing at all.
Is there any way that I can assemble variable names like that in django templating language?

• michjnich: Does this answer your question? Django - iterate number in for loop of a template
• Youssef Ihab: @michjnich No, what I am trying to do is obj.length.1 , then obj.length.2 so I want that value of 1 or 2 to be appended to the variable name itself then to get the value of that variable.

Answer 1

You might register a custom filter (cf. documentation) to achieve what you want:

@register.filter()
def get(obj, attr):
 if hasattr(obj, attr):
 return getattr(obj, attr)
 return obj[attr]

You could then use it like that in your template:

{{ obj.length|get:forloop.counter }}

This being said, I wonder if you could not directly iterate obj or obj.length itself. Are you sure you cannot do something like that in your template? That would be much cleaner.

{% for item in obj %}
 {% comment %}Do something with item{% endcomment %}
{% endfor %}

• Youssef Ihab: That should work, but actually it didn't because the variable contains JSON. I explained my question in details there: stackoverflow.com/questions/71736058/… if you can help :)