django:使用列表中的项而不在视图中执行for循环

我建议你换一下 related_name 你的属性 Like 模型,甚至可以删除它以使用默认名称:

class Like(models.Model):
    liker = models.ForeignKey(User)
    photo = models.ForeignKey(Photo)
    liked = models.BooleanField()

现在您可以这样使用它:

all_likes_of_a_user = user_instance.like_set.all()
all_likes_of_a_photo = photo_instance.like_set.all()

现在,要迭代视图中的照片,可以使用:

for photo in Photo.objects.all():
    like_count = photo.like_set.count()
    has_liked = photo.like_set.filter(liker=request.user).exists()

为了在模板中使用它,可以添加一个嵌套循环:

{% for photo in Photo.objects.all %}
    Like count: {{ photo.like_set.count }}
    Has this user liked this photo:
    {% for like in photo.like_set.all %}
        {% if like.liker == user %}
        yes
        {% endif %}
    {% endfor %}
{% endfor %}

或向您的 Photo 模型:

class Photo(models.Model):
    ...
    def users_that_liked_it(self):
        return [
            e.liker.pk
            for e in self.like_set.all()]

{% for photo in Photo.objects.all %}
    Like count: {{ photo.like_set.count }}
    Has this user liked this photo:
    {% if user.pk in photo.users_that_liked_it %}
        yes
    {% else %}
        no
    {% endif %}
{% endfor %}