python - 如果日期时间早于 Python 中的 x 个月，如何锻炼

Question

我想知道某个条目在过去 6 个月内是否有更新。

这是我试过的:

 def is_old(self):
        """
        Is older than 6 months (since last update)
        """
        time_threshold = datetime.date.today() - datetime.timedelta(6*365/12)
        if self.last_update < time_threshold:
            return False
        return True

但是我得到了错误:

    if self.last_update < time_threshold:
TypeError: can't compare datetime.datetime to datetime.date

Answer 1

你需要days关键字

>>> import datetime
>>> datetime.date.today() - datetime.timedelta(days=30)
datetime.date(2014, 5, 26)
>>> datetime.date.today() - datetime.timedelta(days=180)
datetime.date(2013, 12, 27)
>>> datetime.date.today() - datetime.timedelta(days=6*365/12)
datetime.date(2013, 12, 25)

另外，你的实际错误是:TypeError: can't compare datetime.datetime to datetime.date

你可以这样做

def is_old(self):

    time_threshold = datetime.date.today() - datetime.timedelta(days=6*365/12)

    #The following code can be simplified, i shall let you figure that out yourself. 
    if self.last_update and self.last_update.date() < time_threshold:
        return False
    return True