Django: Filter to check if string contains substring

Out of all the handy filtery things that Django comes with, surprisingly it doesn't have one for checking if a string is contained within another.

Don't worry, thats easy enough to implement.

In a new template tag file:

view sourceprint?

01.from django import template

02.register = template.Library()

03. 

04.@register.filter()

05.def contains(value, arg):

06.  """

07.  Usage:

08.  {% if text|contains:"http://" %}

09.  This is a link.

10.  {% else %}

11.  Not a link.

12.  {% endif %}

13.  """

14.   

15.  return arg in value

Now just make sure the tag file is loaded in the template before using.