如何检查两个日期之间的差异（以秒为单位）？
问题描述：
必须有一种更简单的方法来执行此操作。我有想要经常刷新的对象，因此我想记录它们的创建时间，对照当前时间戳进行检查，并根据需要刷新。
There has to be an easier way to do this. I have objects that want to be refreshed every so often, so I want to record when they were created, check against the current timestamp, and refresh as necessary.
datetime.datetime已证明很困难，我不想进入ctime库。这样的事情有什么容易的吗？
datetime.datetime has proven to be difficult, and I don't want to dive into the ctime library. Is there anything easier for this sort of thing?
答
如果要计算两个已知日期之间的差异，请使用 total_seconds 像这样：
if you want to compute differences between two known dates, use total_seconds like this:
import datetime as dt
a = dt.datetime(2013,12,30,23,59,59)
b = dt.datetime(2013,12,31,23,59,59)
(b-a).total_seconds()
86400.0
#note that seconds doesn't give you what you want:
(b-a).seconds
0