赋值前引用的局部变量 'like'

Question

我在尝试加载页面时遇到以下错误：local variable 'like' referenced before assignment。在我的上下文中，它可以追溯到 "like": like,。

有人可以帮我解决这个问题吗？

谢谢！

views.py:

def photo_detail(request, photo_slug):
    photos = Photo.objects.filter(slug=photo_slug)
    obj = get_object_or_404(Photo, slug=photo_slug)
    all_comments = obj.comment_set.all()
    truncate_amount = 3
    display_comments = obj.comment_set.all()[:int(truncate_amount)]
    for c in all_comments:
        c.get_children()
    comment_form = CommentForm()

    try: 
        like = Like.objects.get(pk=obj.id)
    except Like.DoesNotExist:
    pass

    context = {
        "all_comments": all_comments,
        "comment_form": comment_form,
        "display_comments": display_comments,
        "like": like,
        "obj": obj,
        "photos": photos,
        "truncate_amount": truncate_amount
    }
    return render(request, "photos/photo_detail.html", context)

Answer 1

如果你得到一个 Like.DoesNotExist 异常，你只是 pass，没有分配任何东西给 like。但是无论如何你都会尝试使用它。因此，错误告诉您您在为其分配任何内容之前尝试使用它。

如果你想分配一些 "fallback" 值，比如 None，你可以明确地这样做：

try: 
    like = Like.objects.get(pk=obj.id)
except Like.DoesNotExist:
    like = None

赋值前引用的局部变量 'like'

local variable 'like' referenced before assignment

python

django

django-views

django-errors