英文:
Django datetime field prints out unsupported operand type error
问题
I have a @property in my django model which prints out True or False based on datetime difference. Even though it works when I am unittesting it I get error
TypeError: unsupported operand type(s) for -: 'datetime.datetime' and 'datetime.date'
class MyModel(models.Model):
...
created_at = models.DateTimeField(auto_now_add=True)
@property
def is_expired(self):
if datetime.now(tz=utc) - self.created_at > timedelta(hours=48):
return True
return False
How do I fix this? Every answer I checked does not help me.
英文:
I have a @property in my django model which prints out True or False based on datetime difference. Even though it works when I am unittesting it I get error
TypeError: unsupported operand type(s) for -: 'datetime.datetime' and 'datetime.date'
class MyModel(models.Model):
...
created_at = models.DateTimeField(auto_now_add=True)
@property
def is_expired(self):
if datetime.now(tz=utc) - self.created_at > timedelta(hours=48):
return True
return False
How do I fix this? Every answer I checked does not help me .
答案1
得分: 1
> 不支持的操作数类型：'datetime.datetime'和'datetime.date'
这表示您不能从datetime.date中减去datetime.datetime。在您的情况下，self.created_at似乎是一个date，但您对datetime.now()和timedelta()的使用表明您实际上想处理datetime。
因此，解决方案要么是
- 确保
created_at是一个datetime，或者 - 将
datetime.now()更改为date.today()，并将timedelta(hours=48)更改为timedelta(days=2)。
这两种方法的行为略有不同，因此根据物品在两个日历日后到期还是在48小时后到期的情况选择其中之一。
英文:
The traceback error is explaining the problem to you:
> unsupported operand type(s) for -: 'datetime.datetime' and 'datetime.date'
This says that you cannot subtract a datetime.datetime from a datetime.date. In your case, self.created_at appears to be a date but your use of datetime.now() and timedelta() suggest that you really want to be dealing with datetimes.
Therefore, the solution is to either
- make sure that
created_atis adatetime, or - change
datetime.now()todate.today()and changetimedelta(hours=48)totimedelta(days=2)
These will behave a little differently so pick one depending on whether things expire after two calendar days or in 48 hours.
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