如何对日期时间或日期对象的列表进行排序？

如何对日期和/或日期时间对象的列表进行排序:

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???

python
list
date
sorting
datetime

217016 次浏览

小开

最佳答案

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.

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.