Python速度测试 - 时差 - 毫秒 [英] Python speed testing - Time Difference - milliseconds

问题描述

在Python中比较2次的正确方式是为了加快测试一段代码？我尝试阅读API文档。我不知道我明白了timedelta的事情。

What is the proper way to compare 2 times in Python in order to speed test a section of code? I tried reading the API docs. I'm not sure I understand the timedelta thing.

到目前为止，我有这个代码：

So far I have this code:

from datetime import datetime

tstart = datetime.now()
print t1

# code to speed test

tend = datetime.now()
print t2
# what am I missing?
# I'd like to print the time diff here

推荐答案

datetime.timedelta 只是两个datetimes之间的区别...所以它就像一段时间，以天/秒/微秒

datetime.timedelta is just the difference between two datetimes ... so it's like a period of time, in days / seconds / microseconds

>>> a = datetime.datetime.now()
>>> b = datetime.datetime.now()
>>> c = b - a

>>> c
datetime.timedelta(0, 4, 316543)
>>> c.days
0
>>> c.seconds
4
>>> c.microseconds
316543

注意 c.microseconds 只返回timedelta的微秒部分！为了计时，总是使用 c.total_seconds（）。

Be aware that c.microseconds only returns the microseconds portion of the timedelta! For timing purposes always use c.total_seconds().

您可以使用datetime.timedelta进行各种数学，例如：

You can do all sorts of maths with datetime.timedelta, eg:

>>> c / 10
datetime.timedelta(0, 0, 431654)

可能更多有用的是看CPU时间而不是wallclock时间，虽然...这是操作系统依赖于...在类Unix系统下，查看'时间'命令。

It might be more useful to look at CPU time instead of wallclock time though ... that's operating system dependant though ... under Unix-like systems, check out the 'time' command.

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