Question

Is there a shortcut for the pieces of code described below:

if value.tzinfo is None:
    value = default_tzinfo.localize(value)
    new_value = value.astimezone(default_tzinfo)
else:
    new_value = value

I tried to use datetime.replace() but returns GMT -8 instead of -7 when I use US/Pacific time zone.

See: http://wwp.greenwichmeantime.com/time-zone/usa/pacific-time/pacific-daylight-time.htm

value = value.replace(tzinfo=default_tzinfo)

Example output:

2012-05-06 13:12:45-08:00
US/Pacific
---
2012-05-07 00:12:45+03:00
Europe/Istanbul

Answer 1

The answer is given in the pytz documentation: http://pytz.sourceforge.net/#localized-times-and-date-arithmetic

Once you’ve used localize you should have a datetime with the proper timezone. The call to astimezone is redundant and may be messing you up.

The time zone needs to know the date and time so that it can adjust itself for daylight savings transitions. That’s why replace doesn’t work.