无法使用python中的posix样式时区解析解析时间字符串

Question

我有这样的时间字符串: 2013-08-22 16:56:19 Etc/GMT

我需要将它解析为datetime对象.我陷入了posix风格的时区,我无法让Python本地化.

这是一些尝试和他们的失败.我首先包括时区剥离版本,以显示解析是否正确.

datetime.strptime

>>> datetime.datetime.strptime("2013-08-22 16:56:19 UTC", "%Y-%m-%d %H:%M:%S %Z")
datetime.datetime(2013, 8, 22, 16, 56, 19)
>>> datetime.datetime.strptime("2013-08-22 16:56:19 Etc/GMT", "%Y-%m-%d %H:%M:%S %Z")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/_strptime.py", line 325, in _strptime
    (data_string, format))
ValueError: time data '2013-08-22 16:56:19 Etc/GMT' does not match format '%Y-%m-%d %H:%M:%S %Z'

time.strptime

>>> time.strptime("2013-08-22 16:56:19 UTC", "%Y-%m-%d %H:%M:%S %Z")
time.struct_time(tm_year=2013, tm_mon=8, tm_mday=22, tm_hour=16, tm_min=56, tm_sec=19, tm_wday=3, tm_yday=234, tm_isdst=0)
>>> time.strptime("2013-08-22 16:56:19 Etc/GMT", "%Y-%m-%d %H:%M:%S %Z")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/_strptime.py", line 454, in _strptime_time
return _strptime(data_string, format)[0]
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/_strptime.py", line 325, in _strptime
    (data_string, format))
ValueError: time data '2013-08-22 16:56:19 Etc/GMT' does not match format '%Y-%m-%d %H:%M:%S %Z'

dateutil.parser

>>> dateutil.parser.parse("2013-08-22 16:56:19")
datetime.datetime(2013, 8, 22, 16, 56, 19)
>>> dateutil.parser.parse("2013-08-22 16:56:19 Etc/GMT")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/python_dateutil-2.1-py2.7.egg/dateutil/parser.py", line 720, in parse
    return DEFAULTPARSER.parse(timestr, **kwargs)
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/python_dateutil-2.1-py2.7.egg/dateutil/parser.py", line 310, in parse
    raise ValueError("unknown string format")
ValueError: unknown string format

可能的解决方案/途径尝试过

tzinfos

似乎dateutil的tzinfos论证应该是完美的,但它也不起作用......或者我误读了痕迹并做错了什么.(我以此为例)

>>> dateutil.parser.parse("2013-08-22 16:56:19 Etc/GMT", tzinfos={ 'Etc/GMT': pytz.timezone('UTC') })
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/python_dateutil-2.1-py2.7.egg/dateutil/parser.py", line 720, in parse
    return DEFAULTPARSER.parse(timestr, **kwargs)
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/python_dateutil-2.1-py2.7.egg/dateutil/parser.py", line 310, in parse
    raise ValueError("unknown string format")
ValueError: unknown string format

tzinfos,第二轮

看起来这个stackoverflow的答案正朝着我可能需要的tzinfos的使用方向发展.我尝试了上面的简化版本(其中value = offset seconds).仍然失败.

>>> dateutil.parser.parse("2013-08-22 16:56:19 Etc/GMT", tzinfos={ 'Etc/GMT': 0 })
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/python_dateutil-2.1-py2.7.egg/dateutil/parser.py", line 720, in parse
    return DEFAULTPARSER.parse(timestr, **kwargs)
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/python_dateutil-2.1-py2.7.egg/dateutil/parser.py", line 310, in parse
    raise ValueError("unknown string format")
ValueError: unknown string format

做错了

我总是可以使用正则表达式或字符串匹配来查找和更改此时区,但感觉不对.

红鲱鱼

posix ETC/xxx时区的常见问题是它们具有相反的符号.这是一个UTC("无偏移")posix时区,我发现处理"等"的许多问题都与这个反向偏移有关.

Answer 1

这个怎么样：

• 将不带时区部分的日期字符串解析为datetime对象strptime()
• 将时区字符串解析为时pytz区
• 通过更新tzinfo日期时间对象replace()

from datetime import datetime
import pytz

date_string = "2013-08-22 16:56:19"
tz_string = "Etc/GMT"


dt = datetime.strptime(date_string, "%Y-%m-%d %H:%M:%S")
dt = dt.replace(tzinfo=pytz.timezone('Etc/GMT'))
print dt

印刷：

2013-08-22 16:56:19+00:00

这实际上正确地理解并反转了 POSIX 时区格式中的符号，例如：

dt = dt.replace(tzinfo=pytz.timezone('Etc/GMT-1'))
print dt  # prints 2013-08-22 16:56:19+01:00