I have a Django app where users post photos, and other leave comments under the photos.
When a comment is left, I need to notify:
For (1), I do:
# I slice by 25 because I arbitrarily deem anyone beyond that irrelevant.
all_commenter_ids = (
PhotoComment.objects
.filter(which_photo=which_photo)
.order_by('-id')
.values_list('submitted_by', flat=True)[:25]
)
Next, for (2), I try:
all_relevant_ids = all_commenter_ids.append(which_photo.owner_id)
all_relevant_ids = list(set(all_relevant_ids))
I end up with an error:
'ValuesListQuerySet' object has no attribute 'append'
I find this strange, because I'm extracting a values_list.
Isn't that a list object, and in that case, shouldn't the attribute append
work in this scenario? Please explain what's wrong, and suggest alternatives.
The values_list
method returns a ValuesListQuerySet
. This means it has the advantages of a queryset. For example it is lazy, so you only fetch the first 25 elements from the database when you slice it.
To convert it to a list, use list()
.
all_commenter_ids = PhotoComment.objects.filter(which_photo=which_photo).order_by('-id').values_list('submitted_by', flat=True)[:25]
all_commenter_ids = list(all_commenter_ids)
You might be able to start the queryset from your User
model instead of using values_list
. You haven't shown your models, so the following code is a guess:
from django.db.models import Q
commenters = User.objects.filter(Q(id=which_photo.owner_id)|Q(photocomment=which_photo))