Python 如何对日期时间或日期对象列表进行排序？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/14472795/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How do I sort a list of datetime or date objects?
提问by user_78361084
How do I sort a list of date and/or datetime objects? The accepted answer hereisn't working for me:
如何对日期和/或日期时间对象列表进行排序？接受的答案在这里是不是为我工作：
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???
采纳答案by Volatility
You're getting Nonebecause 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 aagain.
你得到None，因为list.sort()它运行在原地，这意味着它不返回任何东西，但修改列表本身。您只需要调用a.sort()而无需a再次分配。
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.
有一个内置函数sorted()，它返回列表的排序版本 -a = sorted(a)也可以执行您想要的操作。
