python - Django - __str__ 方法不起作用，表示名称未定义

Question

我定义了以下模型。

class Response(models.Model):

  question = models.ForeignKey(Question, on_delete = models.CASCADE)

  STATEMENT_CHOICES = (
    (-1, "Strongly Disagree"),
    (-0.5, "Somewhat Disagree"),
    (0, "Uncertain"),
    (0.5, "Somewhat Agree"),
    (1, "Strongly Agree"),
  )

  statement = models.DecimalField(
    max_digits=2,
    decimal_places=1,
    choices = STATEMENT_CHOICES
  )

  def __str__(self):
    return self.statement

当我运行 django shell 时，我创建一个问题 q ，表示 you like Pizza 和响应 r ，即 1 表示强烈同意。然后，当我在 r 上运行 __str__ 方法时，出现错误，提示 name 'statement' is not Define。

这是确切的控制台输出...

>>> q
<Question: You like pizza.>
>>> r = Response(question=q, statement=1)
>>> r.question
<Question: You like pizza.>
>>> r.statement
1
>>> r
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/TN/Documents/Programming/Django/Practice/myve  /lib/python3.5/site-packages/django/db/models/base.py", line 572, in __repr__
    u = six.text_type(self)
  File "/Users/TN/Documents/Programming/Django/Practice/mysite/personalityQuiz/models.py", line 48, in __str__
    return self.statement
NameError: name 'statement' is not defined

Answer 1

使用self.get_statement_display()返回选项的描述。请参阅the docs了解更多信息。