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I'm trying to convert timezone aware datetime object to UTC and then back to it's original timezone. I have a following snippet
t = datetime( 2013, 11, 22, hour=11, minute=0, tzinfo=pytz.timezone('Europe/Warsaw') ) now in ipython:
In [18]: t Out[18]: datetime.datetime( 2013, 11, 22, 11, 0, tzinfo=<DstTzInfo 'Europe/Warsaw' WMT+1:24:00 STD> ) and now let's try to do conversion to UTC and back. I would expect to have the same representation as:
In [19]: t.astimezone(pytz.utc).astimezone(pytz.timezone('Europe/Warsaw')) Out[19]: datetime.datetime( 2013, 11, 22, 10, 36, tzinfo=<DstTzInfo 'Europe/Warsaw' CET+1:00:00 STD> ) Yet we see that Out[18] and Out[19] differ. What's going on?
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Introduction. pytz brings the Olson tz database into Python. This library allows accurate and cross platform timezone calculations using Python 2.4 or higher. It also solves the issue of ambiguous times at the end of daylight saving time, which you can read more about in the Python Library Reference ( datetime.
Timezone-aware objects are Python DateTime or time objects that include timezone information. An aware object represents a specific moment in time that is not open to interpretation.
tzinfo is an abstract base class. It cannot be instantiated directly. A concrete subclass has to derive it and implement the methods provided by this abstract class. The instance of the tzinfo class can be passed to the constructors of the datetime and time objects.
The documentation http://pytz.sourceforge.net/ states "Unfortunately using the tzinfo argument of the standard datetime constructors 'does not work' with pytz for many timezones." The code:
t = datetime( 2013, 5, 11, hour=11, minute=0, tzinfo=pytz.timezone('Europe/Warsaw') ) doesn't work according to this, instead you should use the localize method:
t = pytz.timezone('Europe/Warsaw').localize( datetime(2013, 5, 11, hour=11, minute=0)) If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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