I was wondering if there was a ternary operator (condition ? true-value : false-value) that could be used in a Django template. I see there is a python one (true-value if condition else false-value) but I'm unsure how to use that inside a Django template to display the html given by one of the values. Any ideas?
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6 Answers
5 Comments
Nandeep Mali
Brilliant. Thank you for the answer. I knew this existed, but couldn't remember.
ivkremer
Very nice and simple, but when I want to use some variables it seems this filter is not applicable. For instance I would like to use
{{ expr_or_value | yesno : "the string", other_variable_value }}
Pepedou
This should be the selected answer! This is exactly what's being asked.
Reimus Klinsman
The documentation doesn't state it but you can also do
{{ value|yesno: "checked," }} if you want to use this for presetting checkboxes
RSK
Agree with @ivkremer. This doesn't work if you need to use variables. Any solution for that?
Why would you need a ternary operator within a template? {% if %} and {% else %} are all you need.
Or you could try the firstof tag:
{% firstof var1 var2 var3 %} which outputs the first one of var1, var2 or var3 which evaluates to a True value.
5 Comments
Anon
I suppose you're right, I'll just use if/else. Just addicted to ternary I guess.
Seth
I would like to see ternary support, too.
B Robster
I tend to disagree with Daniel. I recently converted a django template to a simple javascript template:
{% if data_complete %}{{ data }}{% else %}{{ something_else }}{% endif %} became <%= data_complete ? data : something_else %> ... the second is so much more compact and elegant. It would be nice if there was an equivalent in django.
Vadorequest
"why would you" ... well, to do something in 30 sec instead of 10mn, for instance. Django templating isn't so developer-friendly, it's not always a good thing to have to do stuff in the view instead of the template.
cikatomo
because if else is damn pain in the eye to see and write and it goes of the screen
<a class="btn {% if prospect.has_been_called %}btn-warning{% else %}btn-success{% endif %} d-block" We want ternary, just like we wanted wheels 10000 years agoJust because they haven't been mentioned here yet: the built in template tags default, and default_if_none can be useful in simple circumstances:
default
If value evaluates to False, uses the given default. Otherwise, uses the value.
For example:
{{ value|default:"nothing" }}If value is "" (the empty string), the output will be nothing.
default_if_none
If (and only if) value is None, uses the given default. Otherwise, uses the >value.
Note that if an empty string is given, the default value will not be used. Use >the default filter if you want to fallback for empty strings.
For example:
{{ value|default_if_none:"nothing" }}If value is None, the output will be the string "nothing".
https://docs.djangoproject.com/en/1.9/ref/templates/builtins/#default
2 Comments
ptim
See also: stackoverflow.com/questions/7590198/…
Bono
Too bad this doesn't work for unknown attributes, would have been nice.
I've just implemented the ternary operator for Django as a tag, see https://github.com/alexei/django-template-extensions You can use it as:
{% ?: exp1 exp2 exp3 %} {% ?: exp1 exp2 %} Or:
{% iif exp1 exp2 exp3 %} {% iif exp1 exp2 %} I figured out that it makes more sense than the yesno filter, even though it's really not that Pythonic.
1 Comment
ptim
Awesome, thanks! Solves the issue that I can't pass context variables to
|yesnoYou don't. The Django {% if %} templatetag has only just started supporting ==, and, etc. {% if cond %}{% else %}{% endif %} is as compact as it gets for now.
Comments
I wonder if the python and/or trick would work?
condition and true_value or false_value behaves a like the ternary operator - outputs true_value if condition evaluates to True, and false_value if not.
