CODEWITHSUNDEEP
pythondatetimetimestamptimezone
user503853
user503853

Reputation:

How to convert GMT time to EST time using Python

I want convert GMT time to EST time and get a timestamp. I tried the following but don't know how to set time zone.

time = "Tue, 12 Jun 2012 14:03:10 GMT"
timestamp2 = time.mktime(time.strptime(time, '%a, %d %b %Y %H:%M:%S GMT'))

Upvotes: 20

Views: 61242

Answers (4)

FObersteiner
FObersteiner

Reputation: 25544

With Python 3.9, time zone handling is built into the standard lib with the zoneinfo module (for older Python versions, use zoneinfo via backports.zoneinfo).

Ex:

from zoneinfo import ZoneInfo
from datetime import datetime, timezone

time = "Tue, 12 Jun 2012 14:03:10 GMT"

# parse to datetime, using %Z for the time zone abbreviation
dtobj = datetime.strptime(time, '%a, %d %b %Y %H:%M:%S %Z')

# note that "GMT" (=UTC) is ignored:
# datetime.datetime(2012, 6, 12, 14, 3, 10)

# ...so let's correct that:
dtobj = dtobj.replace(tzinfo=timezone.utc)
# datetime.datetime(2012, 6, 12, 14, 3, 10, tzinfo=datetime.timezone.utc)

# convert to US/Eastern (EST or EDT, depending on time of the year)
dtobj = dtobj.astimezone(ZoneInfo('US/Eastern'))
# datetime.datetime(2012, 6, 12, 10, 3, 10, tzinfo=zoneinfo.ZoneInfo(key='US/Eastern'))
print(dtobj)
# 2012-06-12 10:03:10-04:00

And there's also dateutil, which follows the same semantics:

import dateutil
# no strptime needed...
# correctly localizes to GMT (=UTC) directly
dtobj = dateutil.parser.parse(time) 

dtobj = dtobj.astimezone(dateutil.tz.gettz('US/Eastern'))
# datetime.datetime(2012, 6, 12, 10, 3, 10, tzinfo=tzfile('US/Eastern'))
print(dtobj)
# 2012-06-12 10:03:10-04:00

Upvotes: 11

jfs
jfs

Reputation: 414139

If it is your local timezone and the timezone rules are the same for the given time as they are now then you could use stdlib-only solution (except for some edge cases):

#!/usr/bin/env python
from email.utils import parsedate_tz, mktime_tz
from datetime import datetime

timestamp = mktime_tz(parsedate_tz("Tue, 12 Jun 2012 14:03:10 GMT"))
print(datetime.fromtimestamp(timestamp))
# -> 2012-06-12 10:03:10

Otherwise you need data from a historical timezone database to get the correct utc offset. pytz module provides access to the tz database:

#!/usr/bin/env python
from email.utils import parsedate_tz, mktime_tz
from datetime import datetime
import pytz # $ pip install pytz

timestamp = mktime_tz(parsedate_tz("Tue, 12 Jun 2012 14:03:10 GMT"))
eastern_dt = datetime.fromtimestamp(timestamp, pytz.timezone('America/New_York'))
print(eastern_dt.strftime('%a, %d %b %Y %H:%M:%S %z (%Z)'))
# -> Tue, 12 Jun 2012 10:03:10 -0400 (EDT)

Note: POSIX timestamp is the same around the world i.e., your local timezone doesn't matter if you want to find the timestamp (unless your timezone is of "right" kind). Here's how to convert a utc time to the timestamp.

Upvotes: 0

shiva
shiva

Reputation: 2770

Using pytz

from datetime import datetime
from pytz import timezone
fmt = "%Y-%m-%d %H:%M:%S %Z%z"
now_time = datetime.now(timezone('US/Eastern'))
print now_time.strftime(fmt)

Upvotes: 14

Mark Ransom
Mark Ransom

Reputation: 308121

Time zones aren't built into standard Python - you need to use another library. pytz is a good choice.

>>> gmt = pytz.timezone('GMT')
>>> eastern = pytz.timezone('US/Eastern')
>>> time = "Tue, 12 Jun 2012 14:03:10 GMT"
>>> date = datetime.datetime.strptime(time, '%a, %d %b %Y %H:%M:%S GMT')
>>> date
datetime.datetime(2012, 6, 12, 14, 3, 10)
>>> dategmt = gmt.localize(date)
>>> dategmt
datetime.datetime(2012, 6, 12, 14, 3, 10, tzinfo=<StaticTzInfo 'GMT'>)
>>> dateeastern = dategmt.astimezone(eastern)
>>> dateeastern
datetime.datetime(2012, 6, 12, 10, 3, 10, tzinfo=<DstTzInfo 'US/Eastern' EDT-1 day, 20:00:00 DST>)

Upvotes: 29

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