Localizing Epoch Time with pytz in Python

Question

Im working on converting epoch timestamps to dates in different timezones with pytz. What I am trying to do is create a DateTime object that accepts an Olson database timezone and an epoch time and returns a localized datetime object. Eventually I need to answer questions like "What hour was it in New York at epoch time 1350663248?"

Something is not working correctly here:

import datetime, pytz, time

class DateTime:
    def __init__(self, timezone, epoch):
        self.timezone = timezone
        self.epoch = epoch
        timezoneobject = pytz.timezone(timezone)
        datetimeobject = datetime.datetime.fromtimestamp( self.epoch )
        self.datetime = timezoneobject.localize(datetimeobject)

    def hour(self):
        return self.datetime.hour

if __name__=='__main__':
    epoch = time.time()
    dt = DateTime('America/Los_Angeles',epoch)
    print dt.datetime.hour
    dt = DateTime('America/New_York',epoch)
    print dt.datetime.hour

This prints the same hour, whereas one should be 3 or so hours ahead. Whats going wrong here? I'm a total Python beginner, any help is appreciated!

You are using the wrong terminology here. The epoch is always 1-1-1970, midnight UTC. What you have is a UNIX timestamp, which is an offset from the epoch. See en.wikipedia.org/wiki/Unix_epoch — Martijn Pieters
– Martijn Pieters, Commented Oct 19, 2012 at 16:25
just a variable name, you could call it epoch_time it makes no difference to the problem — mobiusinversion
– mobiusinversion, Commented Oct 20, 2012 at 15:31

jfs · Accepted Answer · 2017-09-14 18:23:21Z

40

datetime.fromtimestamp(self.epoch) returns localtime that shouldn't be used with an arbitrary timezone.localize(); you need utcfromtimestamp() to get datetime in UTC and then convert it to a desired timezone:

from datetime import datetime
import pytz

# get time in UTC
utc_dt = datetime.utcfromtimestamp(posix_timestamp).replace(tzinfo=pytz.utc)

# convert it to tz
tz = pytz.timezone('America/New_York')
dt = utc_dt.astimezone(tz)

# print it
print(dt.strftime('%Y-%m-%d %H:%M:%S %Z%z'))

Or a simpler alternative is to construct from the timestamp directly:

from datetime import datetime
import pytz

# get time in tz
tz = pytz.timezone('America/New_York')
dt = datetime.fromtimestamp(posix_timestamp, tz)
# print it
print(dt.strftime('%Y-%m-%d %H:%M:%S %Z%z'))

It converts from UTC implicitly in this case.

edited Sep 14, 2017 at 18:23

answered Nov 6, 2012 at 21:53

jfs

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Comments

Moinuddin Quadri · Accepted Answer · 2018-09-26 21:17:53Z

6

For creating the datetime object belonging to particular timezone from a unix timestamp, you may pass the pytz object as a tz parameter while creating your datetime. For example:

>>> from datetime import datetime
>>> import pytz

>>> datetime.fromtimestamp(1350663248, tz= pytz.timezone('America/New_York'))
datetime.datetime(2012, 10, 19, 12, 14, 8, tzinfo=<DstTzInfo 'America/New_York' EDT-1 day, 20:00:00 DST>)

You can get the list of all timezones using pytz.all_timezones which returns exhaustive list of the timezone names that can be used.

Also take a look at List of tz database time zones wiki.

edited Sep 26, 2018 at 21:17

answered Jan 2, 2018 at 15:41

Moinuddin Quadri

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Comments

cam · Accepted Answer · 2012-10-19 16:28:11Z

-3

epochdt = datetime.datetime.fromtimestamp(epoch)
timezone1 = timezone("Timezone/String")
adjusted_datetime = timezone1.localize(epochdt)

Working from memory, so excuse any syntax errors, but that should get you on the right track.

EDIT: Missed the part about knowing the hour,etc. Python has great Time/Date Formatting. At pretty much the bottom of that link is the table showing how to pull different attributes from the datetime object.

answered Oct 19, 2012 at 16:28

cam

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1 Comment

mobiusinversion Over a year ago

Thats pretty similar to the initial approach, but implementing this still prints out the same hour (in the main code above). Basically its 8am where I am right now. What im trying to figure out is how to get the above code to print 8 and 11m ie for America/Los_Angeles and America/New_York respectively.

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