Just to be clear, this is python 2.6, I am using pytz.
This is for an application that only deals with US timezones, I need to be able to anchor a date (today), and get a unix timestamp (epoch time) for 8pm and 11pm in PST only.
This is driving me crazy.
> pacific = pytz.timezone("US/Pacific") > datetime(2011,2,11,20,0,0,0,pacific) datetime.datetime(2011, 2, 11, 20, 0, tzinfo=<DstTzInfo 'US/Pacific' PST-1 day, 16:00:0 STD>) > datetime(2011,2,11,20,0,0,0,pacific).strftime("%s") '1297454400' zsh> date -d '@1297454400' Fri Feb 11 12:00:00 PST 2011
So, even though I am setting up a timezone, and creating the datetime with that time zone, it is still creating it as UTC and then converting it. This is more of a problem since UTC will be a day ahead when I am trying to do the calculations.
Is there an easy (or at least sensical) way to generate a timestamp for 8pm PST today?
(to be clear, I do understand the value of using UTC in most situations, like database timestamps, or for general storage. This is not one of those situations, I specifically need a timestamp for evening in PST, and UTC should not have to enter into it.)
Create a tzinfo object utc for the UTC time zone, then try this:
#XXX: WRONG (for any timezone with a non-fixed utc offset), DON'T DO IT datetime(2011,2,11,20,0,0,0,pacific).astimezone(utc).strftime("%s")
Edit: As pointed out in the comments, putting the timezone into the datetime constructor isn't always robust. The preferred method using the pytz documentation would be:
pacific.localize(datetime(2011,2,11,20,0,0,0)).astimezone(utc).strftime("%s")
Also note from the comments that strftime("%s") isn't reliable, it ignores the time zone information (even UTC) and assumes the time zone of the system it's running on. It relies on an underlying C library implementation and doesn't work at all on some systems (e.g. Windows).
There are at least two issues:
- you shouldn't pass a timezone with non-fixed UTC offset such as
"US/Pacific" as tzinfo parameter directly. You should use pytz.timezone("US/Pacific").localize() method instead .strftime('%s') is not portable, it ignores tzinfo, and it always uses the local timezone. Use datetime.timestamp() or its analogs on older Python versions instead.
To make a timezone-aware datetime in the given timezone:
#!/usr/bin/env python from datetime import datetime import pytz # $ pip install pytz tz = pytz.timezone("US/Pacific") aware = tz.localize(datetime(2011, 2, 11, 20), is_dst=None)
To get POSIX timestamp:
timestamp = (aware - datetime(1970, 1, 1, tzinfo=pytz.utc)).total_seconds()
(On Python 2.6, see totimestamp() function on how to emulate .total_seconds() method).
