python时间（毫秒）计算

Question

如何计算毫秒，从下面的代码。

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

>>> c

>>> c.days
0
>>> c.seconds
4
>>> c.microseconds

Answer 1

milliseconds = (c.days * 24 * 60 * 60 + c.seconds) * 1000 + c.microseconds / 1000.0

Answer 2

或者，自 2.7 以来的新功能：

c.total_seconds()*1000

(https://docs.python.org/2/library/datetime.html)