In the code below, I am calculating now epoch and beginning of current day epoch.
import time
import pytz
from datetime import datetime
tz1 = pytz.timezone('CST6CDT')
utc = pytz.timezone('UTC')
now = pytz.UTC.localize(datetime.utcnow())
now_tz = now.astimezone(tz1)
print now_tz
print now_tz.strftime('%s')
begin_day = now_tz.replace(hour=0, minute=0, second=0)
print begin_day
print begin_day.strftime('%s')
print statements:
2012-08-28 13:52:21.595718-05:00
1346187141
2012-08-28 00:00:00.595718-05:00
1346137200
Converting epochs to timestamp with CDT timezone: 1346187141 - Aug 28 2012 15:52:21, 1346137200 - Aug 28 2012 02:00:00
I'd like the second epoch to be beginning of the day but it's 2 am. It looks like it is still using local timezone PST when converting to epoch.
What am I doing wrong ? or can this be done a different way?
Thanks!
To convert a datetime with timezone to epoch (POSIX timestamp):
from datetime import datetime
import pytz
tz = pytz.timezone('CST6CDT')
# a datetime with timezone
dt_with_tz = tz.localize(datetime(2012, 8, 28, 19, 33, 50), is_dst=None)
# get timestamp
ts = (dt_with_tz - datetime(1970, 1, 1, tzinfo=pytz.utc)).total_seconds()
# -> 1346200430.0
It is how datetime.timestamp
method is implemented for timezone-aware datetime
objects in Python 3.
To get "now epoch":
from datetime import datetime
now_epoch = (datetime.utcnow() - datetime(1970, 1, 1)).total_seconds()
Or (assuming time
uses POSIX epoch):
import time
now_epoch = time.time()
Getting "beginning of current day epoch" is more complex because current day may be different in different timezones:
from datetime import datetime, time
import pytz
tz = pytz.timezone('CST6CDT')
# get current date in given timezone
today = datetime.now(tz).date()
# -> datetime.date(2013, 6, 22)
# get beginning of current day in given timezone as a datetime with timezone
midnight = tz.localize(datetime.combine(today, time(0, 0)), is_dst=None)
# -> datetime.datetime(2013, 6, 22, 0, 0, tzinfo=<DstTzInfo 'CST6CDT'...>)
# get timestamp
ts = (midnight - datetime(1970, 1, 1, tzinfo=pytz.utc)).total_seconds()
# -> 1371877200.0
See How do I get the UTC time of “midnight” for a given timezone? .
To get "beginning of current day epoch" assuming UTC date:
from datetime import datetime, date
# get current date in UTC
utc_date = datetime.utcnow().date()
# -> datetime.date(2013, 6, 23)
# get timestamp
ts = (utc_date - date(1970, 1, 1)).days * 86400
# -> 1371945600
See Converting datetime.date/datetime.datetime to UTC timestamp in Python .
NOTE: My answer is flat-out wrong. (I'd like to delete it, but am unable to do so until the accept flag is removed.)
Please see JFSebastian's answer .
Here is code demonstrating a value of now_tz
for which our two methods produce different results.
import calendar
import pytz
import datetime as dt
tz1 = pytz.timezone('US/Eastern')
utc = pytz.timezone('UTC')
now = utc.localize(dt.datetime(2002, 10, 28), is_dst=None)
now_tz = now.astimezone(tz1)
now_epoch = calendar.timegm(now_tz.utctimetuple())
begin_day = tz1.normalize(now_tz.replace(hour=0, minute=0, second=0))
midnight = tz1.localize(dt.datetime.combine(now_tz, dt.time(0, 0)), is_dst=None)
if begin_day != midnight:
print(begin_day)
# 2002-10-27 01:00:00-04:00 # my result -- is not midnight
print(midnight)
# 2002-10-27 00:00:00-04:00 # J.F.Sebastian's result is correct
(Original answer redacted)
the latest release of simple-date (version 0.2 on pypi ) will manage the details for you:
>>> from simpledate import *
>>> now_utc = SimpleDate(tz='UTC')
>>> now_tz = now_utc.convert(tz='CST6CDT')
>>> begin_day = now_tz.replace(hour=0, minute=0, second=0, microsecond=0)
>>> now_utc.timestamp
1371950295.777453
>>> now_tz.timestamp
1371950295.777453
>>> begin_day.timestamp
1371877200.0
we can go backwards to check the timestamps (although it's clear above that switching timezone didn't change the epoch, while moving to start of day did):
>>> SimpleDate(1371877200.0, tz='CST6CDT')
SimpleDate('2013-06-22 00:00:00.000000 CDT', tz='CST6CDT')
>>> SimpleDate(1371877200.0, tz='UTC')
SimpleDate('2013-06-22 05:00:00.000000 UTC')
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