I have a Django app where users post photos, and other leave comments under the photos.
我有一个Django应用程序，用户发布照片，其他留下评论照片下。
When a comment is left, I need to notify:
留下评论时，我需要通知：
- Everyone else who wrote in this thread
- 在这个帖子中写道的其他人
- The owner of the photo, in case they're not included in (1)
- 照片的所有者，如果他们不包括在（1）
For (1), I do:
对于（1），我这样做：
#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:
接下来，对于（2），我尝试：
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:
我最终得到一个错误：
'ValuesListQuerySet' object has no attribute 'append'
'ValuesListQuerySet'对象没有属性'append'
I find this strange, because I'm extracting a values_list.
我发现这很奇怪，因为我正在提取一个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.
这不是一个列表对象，在这种情况下，属性追加不应该在这种情况下工作吗？请解释什么是错的，并提出替代方案。
1 个解决方案
#1
19
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.
values_list方法返回ValuesListQuerySet。这意味着它具有查询集的优点。例如，它是惰性的，因此在切片时只能从数据库中获取前25个元素。
To convert it to a list, use list().
要将其转换为列表，请使用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:
您可以从User模型启动查询集，而不是使用values_list。您尚未显示模型，因此以下代码是猜测：
from django.db.models import Q
commenters = User.objects.filter(Q(id=which_photo.owner_id)|Q(photocomment=which_photo))
#1
19
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.
values_list方法返回ValuesListQuerySet。这意味着它具有查询集的优点。例如，它是惰性的，因此在切片时只能从数据库中获取前25个元素。
To convert it to a list, use list().
要将其转换为列表，请使用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:
您可以从User模型启动查询集，而不是使用values_list。您尚未显示模型，因此以下代码是猜测：
from django.db.models import Q
commenters = User.objects.filter(Q(id=which_photo.owner_id)|Q(photocomment=which_photo))