Parentheses in django if statement

Question

How can I do this cleanly in a Django template? Basically if A, or (B and C) , I want to show some HTML.

I basically have this:

{% if user.is_admin or something.enable_thing and user.can_do_the_thing %}

Now, thats a bit ambigious. I tried doing

{% if user.is_admin or (something.enable_thing and user.can_do_thething) %}

But you arent allowed Parentheses. The docs say to use nested ifs (or elifs in this case, i guess, as its an OR) , but I dont want to repeat the same HTML inside 2 if blocks, which sounds horrible.

Solution 1

As Mihai Zamfir commented it should work as expected. As Django documentation mentions:

Use of both and and or clauses within the same tag is allowed, with and having higher precedence than or e.g.:

{% if athlete_list and coach_list or cheerleader_list %}

will be interpreted like:

if (athlete_list and coach_list) or cheerleader_list

https://docs.djangoproject.com/en/2.2/ref/templates/builtins/#boolean-operators

Solution 2

you could do the check in your view and pass a flag to the context.

show_html = user.is_admin or (something.enable_thing and user.can_do_the_thing)
context['show_html'] = show_html

Then in your template you could check the flag

{% if show_html %}

Comments

[Mihai Zamfir]

leave it without paranthesis. I think it works ;)

[Aamir Rind]

You don't want to use nested if's and also parenthesis are invalid in if block, hence clearly framework does not support what you are asking for get over with it and move your complex logic to template tags or views.

[Mihai Zamfir]

I wouldn't put this logic into a view but rather use a custom tag

[mehmet]

What if one of those variables need to be a loop iteration variable? django disappointed me about this.

[Hassan Baig]

Could you provide a link to the official documentation as well? Helpful answer

[Daniel W.]

And inverted: {% if athlete_list and coach_list or athlete_list and cheerleader_list %} would equal if athlete_list and (coach_list or cheerleader_list)