multiplication in django template without using manually created template tag - django-templates

Question

I want to achieve multiplication operation in django template. For example
I have the values,
price=10.50
quantity=3
With the help of this link
http://slacy.com/blog/2010/07/using-djangos-widthratio-template-tag-for-multiplication-division/
i tried below codes for achieving it,
{% widthratio quantity 1 price %}
but its returning only 31. But i need the answer in float (31.5)
And i want to achieve it without using the manually created tags
How can i achieve it?
Thanks in advance...

Answer 1

You can use the built-in widthratio template tag.
a*b use {% widthratio a 1 b %}
a/b use {% widthratio a b 1 %}
Note: the results are rounded to an integer before returning.
#see https://docs.djangoproject.com/en/dev/ref/templates/builtins/

Answer 2

There are 2 approaches:
Computing the values inside the view and pass them to the template (recommended in my opinion)
Using template filters
In the manner of the add filter, you could always create your own multiply filter, creating your own custom filter:
from django import template
register = template.Library()
#register.filter
def multiply(value, arg):
return value * arg
Then in your template, something like that should work.
{{ quantity | multiply:price }}
This is not tested, and I never did this as - again - I find neater to compute datas inside the views and render only with the templates.

Answer 3

Another approach that I have used seems cleaner to me. If you are going through a queryset, it doesn't make sense to compute the values in your view. Instead, add the calculation as a function in your model!
Let's say your model looks like this:
Class LineItem:
product = models.ForeignKey(Product)
quantity = models.IntegerField()
price = models.DecimalField(decimal_places=2)
Simply add the following to the model:
def line_total(self):
return self.quantity * self.price
Now you can simply treat line_total as if it were a field in the record:
{{ line_item.line_total }}
This allows the line_total value to be used anywhere, either in templates or views, and ensures that it is always consistent, without taking up space in the database.

Answer 4

I know it's been so long since this question came out but, now there's a library called django-mathfilters which made mathematical operations easier in Django templates. you can easily write
<li>42 * 0.5 = {{ answer|mul:0.5 }}</li> for multiplication.
check it out https://pypi.org/project/django-mathfilters/

Answer 5

Multiplication with variable in Django.
1st: install & then register "mathfilters" at INSTALLED_APPS in setting.py
2nd: Add {% load mathfilters %} in html Page
3rd: Multiply with variable like{{response.notSatisfied|mul:100}}