django filter for NOT IN as lookup_expr

Question

We can make the django filter with "in" expression sending comma separated string. Such as

import django_filters

class NumberInFilter(django_filters.BaseInFilter, django_filters.NumberFilter):
    pass

class BookFilter(django_filters.FilterSet):
    author = NumberInFilter(field_name="author__id", lookup_expr="in")

However, I was looking for way to send comma separated query-data and get response which do not have the query-data. something like

class BookFilter(django_filters.FilterSet):
    author = NumberInFilter(field_name="author__id", lookup_expr="not_in")

Definitely there is nothing like "not_in". Can you please give me a solution to achieve this?

Answer 1

I'm not sure there is a simple built-in for doing an exlusive lookup in django-filters. However you can probably do this pretty easily with a custom method on your filterset class with a .exclude() :

class BookFilter(django_filters.FilterSet):
    author = django_filters.NumberFilter(method='filter_author')

    def filter_author(self, queryset, name, value):
        return queryset.exclude(author_id__in=value)

Answer 2

Just wanted to add what I finally got,

class BookFilter(django_filters.FilterSet):
    author = django_filters.NumberFilter(method='filter_author')

    def filter_author(self, queryset, name, value):
        if value:
            return queryset.exclude(author__id__in=value.split(','))
        return queryset

Answer 3

Seems there is a more optimal solution. You can use the NumberFilters' exclude=True option like this:

class BookFilter(django_filters.FilterSet):
    author = NumberInFilter(
        field_name="author__id", 
        lookup_expr="in", 
        exclude=True
    )