Python datetime add

Question

我有一个字符串格式的日期时间值.如何将格式从" - "分隔日期更改为".".分开的日期.我还需要增加6个小时才能让数据进入我的时区.

s = '2013-08-11 09:48:49'
from datetime import datetime,timedelta
mytime = datetime.strptime(s,"%Y-%m-%d %H:%M:%S")
time = mytime.strftime("%Y.%m.%d %H:%M:%S")
dt = str(timedelta(minutes=6*60))  #6 hours
time+=dt
print time
print dt

我得到以下结果,它在最后增加了六个小时而不是九个小时:

2013.08.11 09:48:496:00:00
6:00:00

Answer 1

要添加的字符串表示的timedelta():

>>> from datetime import timedelta
>>> print timedelta(minutes=6*60)
6:00:00

求和datetime和timedelta对象,而不是它们的字符串表示; 只在对对象求和后创建一个字符串:

from datetime import datetime, timedelta
s = '2013-08-11 09:48:49'
mytime = datetime.strptime(s, "%Y-%m-%d %H:%M:%S")
mytime += timedelta(hours=6)
print mytime.strftime("%Y.%m.%d %H:%M:%S")

这导致:

>>> from datetime import datetime, timedelta
>>> s = '2013-08-11 09:48:49'
>>> mytime = datetime.strptime(s, "%Y-%m-%d %H:%M:%S")
>>> mytime += timedelta(hours=6)
>>> print mytime.strftime("%Y.%m.%d %H:%M:%S")
2013.08.11 15:48:49

但是,您可能希望使用实时区域对象,我建议您使用该pytz库:

>>> from pytz import timezone, utc
>>> eastern = timezone('US/Eastern')
>>> utctime = utc.localize(datetime.strptime(s, "%Y-%m-%d %H:%M:%S"))
>>> local_tz = utctime.astimezone(eastern)
>>> print mytime.strftime("%Y.%m.%d %H:%M:%S")
2013.08.11 15:48:49

例如,这也将考虑夏令时.