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Date: Mon, 23 May 2011 23:33:40 +1100
Subject: Re: Python 2.6 and timezones
From: Daniel Kluev <dan.kluev@gmail.com>
To: python-list@python.org
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On Mon, May 23, 2011 at 10:56 PM, loial <jldunn2000@gmail.com> wrote:
> Thanks...but being a python newbie I am struggling to understand how
> to do this.
>
> How can I use tzinfo to do the equivalent of what I do in Java, which
> is  :
>
>    TimeZone tz1 = TimeZone.getDefault();
>
>    long localOffset = tz1.getOffset(date.getTime());
>
>    TimeZone tz2 = TimeZone.getTimeZone("EST");
>
>    long remoteOffset = tz2.getOffset(date.getTime());
>

>>> from pytz import timezone, FixedOffset
>>> import time
>>> from datetime import datetime
>>> local_tz = FixedOffset(-time.timezone/60)

time.timezone returns local timezone in seconds and negative sign.
FixedOffset converts it into tzinfo object.

>>> now = datetime.now()
>>> local_tz.utcoffset(now)
datetime.timedelta(0, 36000)

utcoffset() returns timedelta object as offset. It requires datetime
object as first parameter due to weird API of base tzinfo class, but
it is not used in calculation, and you can pass any other object,
including None instead, like `local_tz.utcoffset(None)`

>>> remote_tz = timezone("EST")
>>> remote_tz.utcoffset(now)
datetime.timedelta(-1, 68400)

You can add or substract these timedelta objects directly from
datetime objects or use astimezone():

>>> now = datetime.now(local_tz)
>>> now
datetime.datetime(2011, 5, 23, 22, 41, 48, 398685, tzinfo=pytz.FixedOffset(600))
>>> now.astimezone(remote_tz)
datetime.datetime(2011, 5, 23, 7, 41, 48, 398685, tzinfo=<StaticTzInfo 'EST'>)


-- 
With best regards,
Daniel Kluev