How to filter Charfiled by List of Tags in Django ORM

Question

What is the preferred way to filter CharField using List of Tags? in database i have something like this :

genres = "something, apple ,something_else ,something_else2, orange, grape, more.."

i tried using __in operator nothing comes out

elem = list(Elements.objects.filter(genres__in=['apple','orange','grape']))

Answer 1

You can try this query

elem = list(Elements.objects.filter(Q(genres__icontains="apple") | Q(genres__icontains="orange") | Q(genres__icontains="grape")))

But I think for tags it's a better solution Django Filtering A Blog Based on Tags

Answer 2

You would probably want to use a Q lookup. https://docs.djangoproject.com/en/2.1/topics/db/queries/#complex-lookups-with-q-objects

from django.db.models import Q

elem = Elements.objects.filter(Q(genres__icontains="apple") | Q(genres__icontains="orange") | Q(genres__icontains="grapes"))

Answer 3

I was able to get what i want doing the following:

from django.db.models import Q
from functools import reduce
from operator import and_

tag_list = ['apple', 'orange', 'grape']

query = reduce(and_, (Q(genres__icontains=tag) for tag in tag_list))
elem = list(Elements.objects.filter(query))

You can also use or_ operator see:

How to dynamically compose an OR query filter in Django? '