时区在python中不可用，但系统时区已正确设置

Question

As specified in the documentation :

%Z -> Time zone name (no characters if no time zone exists).

According to date, my system has the time zone properly set:

gonvaled@pegasus ~ » date
Sat Sep 28 09:14:29 CEST 2013

But this test:

def test_timezone():
    from datetime import datetime
    dt = datetime.now()
    print dt.strftime('%Y-%m-%d %H:%M:%S%Z')   
test_timezone()

Produces:

gonvaled@pegasus ~ » python test_timezone.py 
2013-09-28 09:19:10

Without time zone information. Why is that? How can I force python to output time zone info?

I have also trying re-configuring the time zone with tzselect , but has not helped.

Answer 1

Standard Python datetime.datetime() objects do not have a timezone object attached to them. The system time is taken as is.

You'll need to install Python timezone support in the form of the pytz package ; timezone definitions change too frequently to be bundled with Python itself.

pytz does not tell you what timezone your machine has been configured with. You can use the python-dateutil module for that; it has a dateutil.tz.gettz() function that returns the timezone currently in use. This is much more reliable than what Python can get from the limited C API:

>>> import datetime
>>> from dateutil.tz import gettz
>>> datetime.datetime.now(gettz())
datetime.datetime(2013, 9, 28, 8, 34, 14, 680998, tzinfo=tzfile('/etc/localtime'))
>>> datetime.datetime.now(gettz()).strftime('%Y-%m-%d %H:%M:%S%Z')
'2013-09-28 08:36:01BST'