python - django.template.exceptions.TemplateSyntaxError: Could not parse some characters: |{{b.count}}||rangef

Question

I'm trying to loop in a Django template by using a custom filter, but for some reason I receive this error:

django.template.exceptions.TemplateSyntaxError: Could not parse some characters: |{{b.count}}||rangef

myfilters.py

@register.filter(name='rangef')
def rangef(number):
    return range(number)

index.html

<div class="container">
{% for i in {{b.count}}|rangef %}
    <p>Some text</p>
{% endfor %}
</div>

Important to mention that b.count is an Integer field. Appreciate your help!

Answer 1

The custom filter can be used with the following syntax:

{{ b.count | rangef }}

Note that the filter part is inside the curly braces since this will apply the filter rangef to the value on the left, b.count.

Note that filters are not supported within for loops. Consider changing your model so that it exposes the filtered value directly, e.g.

def b_range(self):
    return range(self.b.count)

{% for i in b_range %}
…
{% endfor %}