[Tutor] datetime, time zones, and ISO time

[Kent Johnson]

On Wed, Feb 17, 2010 at 4:37 PM, David Perlman <dperlman at wisc.edu> wrote:
> OK, here's a function that does precisely what I want:
>
> def tzDelta():
>  """by whatever means necessary, return the current offset of the local time
> from utc."""
>  s=time.time()
>  t,u=time.localtime(s),time.gmtime(s)
>  osec=3600*(t[3]-u[3]) + 60*(t[4]-u[4]) + (t[5]-u[5])
>  return datetime.timedelta(seconds=osec)
>
>
> As far as I can tell, this should always work.  So wouldn't it be nice if
> there were a less convoluted way to get this??

Here is a shorter version based on the LocalTimezone example, and it
only gets the time once so there is no possible race condition:

In [5]: from datetime import timedelta

In [6]: import time

In [15]: def utcoffset():
   ....:     if time.localtime().tm_isdst > 0:
   ....:         return timedelta(seconds = -time.altzone)
   ....:     return timedelta(seconds = -time.timezone)
   ....:

In [16]: utcoffset()
Out[16]: datetime.timedelta(-1, 68400)

Kent