Creating custom Field Lookups in Django

Question

How do you create custom field lookups in Django?

When filtering querysets, django provides a set of lookups that you can use: __contains, __iexa

Answer 1

Rather than creating a field lookup, best practice would be to create a manager method, that might look a little bit like this:

class PersonManger(models.Manager):
    def in_age_range(self, min, max):
        return self.filter(age__gte=min, age__lt=max)

class Person(models.Model):
    age = #...

    objects = PersonManager()

then usage would be like so:

twentysomethings = Person.objects.in_age_range(20, 30)