检查日期字符串是否为 UTC 格式

Question

I have a date string like "2011-11-06 14:00:00+00:00". Is there a way to check if this is in UTC format or not?. I tried to convert the above string to a datetime object using utc = datetime.strptime('2011-11-06 14:00:00+00:00','%Y-%m-%d %H:%M%S+%z) so that i can compare it with pytz.utc, but i get 'ValueError: 'z' is a bad directive in format '%Y-%m-%d %H:%M%S+%z'

How to check if the date string is in UTC?. Some example would be really appreciated.

Thank You

Answer 1

A simple regular expression will do:

>>> import re
>>> RE = re.compile(r'^\d{4}-\d{2}-\d{2}[ T]\d{2}:\d{2}:\d{2}[+-]\d{2}:\d{2}$')
>>> bool(RE.search('2011-11-06 14:00:00+00:00'))
True

Answer 2

The problem with your format string is that strptime just passes the job of parsing time strings on to c's strptime , and different flavors of c accept different directives. In your case (and mine, it seems), the %z directive is not accepted.

There's some ambiguity in the doc pages about this. The datetime.datetime.strptime docs point to the format specification for time.strptime which doesn't contain a lower-case %z directive, and indicates that

Additional directives may be supported on certain platforms, but only the ones listed here have a meaning standardized by ANSI C.

But then it also points here which does contain a lower-case %z , but reiterates that

The full set of format codes supported varies across platforms, because Python calls the platform C library's strftime() function, and platform variations are common.

There's also a bug report about this issue.

Answer 3

By 'in UTC format' do you actually mean ISO-8601? . This is a pretty common question .