如何排序日期时间或日期对象的列表？ [英] How do I sort a list of datetime or date objects?

问题描述

如何排序日期和/或日期时间对象的列表？接受的答案此处对我无效：

How do I sort a list of date and/or datetime objects? The accepted answer here isn't working for me:

from datetime import datetime,date,timedelta


a=[date.today(), date.today() + timedelta(days=1), date.today() - timedelta(days=1)]
print a # prints '[datetime.date(2013, 1, 22), datetime.date(2013, 1, 23), datetime.date(2013, 1, 21)]'
a = a.sort()
print a # prints 'None'....what???

推荐答案

您正在获得无因为 list.sort（）它运行就地，这意味着它不返回任何东西，而是修改列表本身。您只需要调用 a.sort（），而不必将它分配到 a 。

You're getting None because list.sort() it operates in-place, meaning that it doesn't return anything, but modifies the list itself. You only need to call a.sort() without assigning it to a again.

有一个内置函数 sorted（），它返回列表的排序版本 - a = sorted（ a）将会做你想要的。

There is a built in function sorted(), which returns a sorted version of the list - a = sorted(a) will do what you want as well.

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