Question

python 时间字符串相减

不标准的时间字符串，没有日期的，但是都是同一天的，比如'12:13:50'减'12:28:21'是多少秒怎么计算？
还有，有什么现成的函数，能把秒转成00:00:00这种格式吗，或者n时n钟n秒，就是想知道两个时间的差，同时看起来直观些~

Answer 1

from datetime import datetime
a = '12:13:50'
b = '12:28:21'
time_a = datetime.strptime(a,'%H:%M:%S')
time_b = datetime.strptime(b,'%H:%M:%S')
print (time_b - time_a).seconds

Answer 2

$ python
Python 2.7.3 (default, Jan 2 2013, 16:53:07)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> patt = re.compile(r'(?P<hour>\d{1,2})\:(?P<minute>\d{2})\:(?P<second>\d{2})')
>>> def strtime2second(s):
... try:
... d = patt.match(s).groupdict()
... return int(d['hour'])*3600+int(d['minute'])*60+int(d['second'])
... except:
... pass
...
>>> a = '12:13:50'
>>> b = '12:28:21'
>>> strtime2second(b) - strtime2second(a)
871
>>>