Modulus % in Django template
PythonDjangoTemplatesPython Problem Overview
I'm looking for a way to use something like the modulus operator in django. What I am trying to do is to add a classname to every fourth element in a loop.
With modulus it would look like this:
{% for p in posts %}
<div class="post width1 height2 column {% if forloop.counter0 % 4 == 0 %}first{% endif %}}">
<div class="preview">
</div>
<div class="overlay">
</div>
<h2>p.title</h2>
</div>
{% endfor %}
Of course this doesn't work because % is a reserved character. Is there any other way to do this?
Python Solutions
Solution 1 - Python
You need divisibleby, a built-in django filter.
{% for p in posts %}
<div class="post width1 height2 column {% if forloop.counter0|divisibleby:4 %}first{% endif %}">
<div class="preview">
</div>
<div class="overlay">
</div>
<h2>p.title</h2>
</div>
{% endfor %}
Solution 2 - Python
You can't use the modulus operator in Django template tags, but it would be easy enough to write a filter to do so. Something like this should work:
@register.filter
def modulo(num, val):
return num % val
And then:
{% ifequal forloop.counter0|modulo:4 0 %}
You could even do something like this, instead:
@register.filter
def modulo(num, val):
return num % val == 0
And then:
{% if forloop.counter0|modulo:4 %}
Or you could use the cycle tag:
<div class="post width1 height2 column {% cycle 'first' '' '' '' %}">
Solution 3 - Python
Bootstrap rows and columns example. New row every 4 items. Also close last row even if there are less than 4 items.
myapp/templatetags/my_tags.py
from django import template
register = template.Library()
@register.filter
def modulo(num, val):
return num % val
html template
{% load my_tags %}
{% for item in all_items %}
{% if forloop.counter|modulo:4 == 1 %}
<div class="row">
{% endif %}
<div class="col-sm-3">
{{ item }}
</div>
{% if forloop.last or forloop.counter|modulo:4 == 0 %}
</div>
{% endif %}
{% endfor %}
Solution 4 - Python
It sounds like you should just use the cycle tag. Built-in template tags