When I run the following in Python 3.X
import datetime
DATE_TS_FORMAT = '%Y-%m-%d %H:%M:%S.%f %Z'
date_ts = datetime.datetime(2019, 1, 2, 3, 4, 5, tzinfo=datetime.timezone.utc)
date_ts = date_ts.strftime(DATE_TS_FORMAT)
print(date_ts)
date_ts = datetime.datetime.strptime(date_ts, DATE_TS_FORMAT)
date_ts = date_ts.strftime(DATE_TS_FORMAT)
print(date_ts)
I get
2019-01-02 03:04:05.000000 UTC
2019-01-02 03:04:05.000000
Why did the timezone information disappear and how can I fix this issue?
Inconsistent indeed... The point is that %Z makes strptime accept certain strings (GMT, UTC and any value in time.tzname - docs), but doesn't actually make anything out of it. Ex:
from datetime import datetime
s = "2019-01-02 03:04:05.000000 UTC"
dt = datetime.strptime(s, '%Y-%m-%d %H:%M:%S.%f %Z')
print(repr(dt))
# datetime.datetime(2019, 1, 2, 3, 4, 5)
The resulting datetime object is naive; no sign of UTC anymore.
To account for this behavior, you could post-process the datetime object, something like
if "UTC" in s:
dt = dt.replace(tzinfo=timezone.utc)
(which I think is a bit painful...) or replace "UTC" with something that %z parses to UTC1,
dt = datetime.strptime(s.replace("UTC", "+00:00"), '%Y-%m-%d %H:%M:%S.%f %z')
print(repr(dt))
# datetime.datetime(2019, 1, 2, 3, 4, 5, tzinfo=datetime.timezone.utc)
(which I think is a bit ugly...) or use a suitable parser, e.g.
from dateutil.parser import parse
dt = parse(s)
print(repr(dt))
# datetime.datetime(2019, 1, 2, 3, 4, 5, tzinfo=tzutc())
print(dt.strftime('%Y-%m-%d %H:%M:%S.%f %Z'))
# 2019-01-02 03:04:05.000000 UTC
(which will be a bit slower if performance is an issue...).
1 IMO, this is inconsistent as well; "+00:00" could also be the UTC offset of some time zone that happens to have a UTC offset of 0 hours at that time...
I have two inputs time 00:00 and timezone 'Asia/Kolkata'
I want to convert this to UTC time like '18.30'
I don't want to add or subtract offsets because it may affect the day light saving
what i did is
local = pytz.timezone ("UTC")
nativetime = datetime.strptime (setTime,frmt)
local_dt = local.localize(nativetime, is_dst=None)
utc_dt = local_dt.astimezone(pytz.utc)
but this doesn't change anything, the time is not converted to UTC
Please help
Something like this, assuming you're on py3:
>>> import datetime
>>> import pytz
>>> tz = pytz.timezone('Asia/Kolkata')
>>> dt = datetime.datetime(2020, 8, 4, 0, 0, tzinfo=tz)
>>> dt.astimezone(pytz.utc)
datetime.datetime(2020, 8, 3, 18, 7, tzinfo=<UTC>)
>>>
Since you say you're new to Python, it might be good to skip pytz since it's going to be deprecated with Python 3.9. You can use dateutil instead, which can be replaced more easily with zoneinfo in Python 3.9.
from datetime import datetime, timezone
from dateutil.tz import gettz
# assuming you have something like
dt_naive = datetime.strptime('2020-08-05', '%Y-%m-%d')
# dt_naive has no time zone info, so set it:
dt_aware = dt_naive.replace(tzinfo=gettz('Asia/Kolkata'))
# now you can convert to another timezone using .astimezone:
dt_aware_utc = dt_aware.astimezone(timezone.utc)
# datetime.datetime(2020, 8, 4, 18, 30, tzinfo=datetime.timezone.utc)
# -> 5:30 hours behind, which matches dt_aware.utcoffset()
#thebjorn gave me the answer
here is what i did
def utc_to_local(utc_dt,local_tz):
local_dt = utc_dt.replace(tzinfo=pytz.utc).astimezone(local_tz)
return local_tz.normalize(local_dt)
setTime='00:00:00'
setZone='Asia/Kolkata'
datePart = str(datetime.utcnow()).split(' ')[0]
dateTimeUtcStr = datePart+' '+str(setTime)
tz = pytz.timezone('Asia/Kolkata')
tz_utc = pytz.timezone('UTC')
dateTimeRef = datetime.strptime(dateTimeUtcStr, '%Y-%m-%d %H:%M:%S')
#local to utc
tzUtc = pytz.timezone('UTC')
local_dt = tz.localize(dateTimeRef, is_dst=None)
utc_dt = local_dt.astimezone(pytz.utc)
print(utc_dt)
#utc to local
altTime = utc_to_local(utc_dt,tz)
print(altTime)
I have two datetime objects, they represent the same datetime value in different timezones. I would like to convert them to POSIX timestamp. However appearently calling datetime.timestamp() returns a value regardless of the timezone.
from datetime import datetime
import pytz
dt = datetime(2020, 7, 26, 6, 0)
utc_dt = pytz.utc.localize(dt) # datetime.datetime(2020, 7, 26, 6, 0, tzinfo=<UTC>)
bp = pytz.timezone("Europe/Budapest")
bp_dt = utc_dt.astimezone(bp) # datetime.datetime(2020, 7, 26, 8, 0, tzinfo=<DstTzInfo 'Europe/Budapest' CEST+2:00:00 DST>)
utc_dt.timestamp() # 1595743200.0
bp_dt.timestamp() # 1595743200.0
The documentation of datetime.timestamp() says the following:
For aware datetime instances, the return value is computed as:
(dt - datetime(1970, 1, 1, tzinfo=timezone.utc)).total_seconds()
Running utc_dt - bp_dt returns datetime.timedelta(0). So it seems it calculates with the UTC value of the datetime objects.
I use Python in a web stack. I want the backend to deal with the timezone handling and the client to recieve the precalculated datetime values in the user's timezone in the API responses.
What is the Pythonic way to get timezone aware timestamps?
In short, I would not recommend doing this because you can create a total mess, see my comment.
Technically, you could do it by simply replacing the tzinfo property of the datetime object with UTC. Note that I'm using dateutil.tz here so I can set the initial timezone directly (no localize()).
from datetime import datetime, timezone
from dateutil import tz
dt = datetime(2020, 7, 26, 6, 0, tzinfo=tz.gettz("Europe/Budapest"))
# dt.utcoffset()
# >>> datetime.timedelta(seconds=7200)
# POSIX timestamp that references to 1970-01-01 UTC:
ts_posix = dt.timestamp()
# timestamp that includes the UTC offset:
ts = dt.replace(tzinfo=timezone.utc).timestamp()
# ts-ts_posix
# >>> 7200.0
Given the following Python datetime object representing an UTC time:
2016-09-15 22:13:03-2:00
I'm trying to obtain the corresponding local time datetime, where the UTC offset is applied:
2016-09-15 20:13:03
I was hoping to find a method in the datetime module that was able to do this, but I did not succeed. Any help is very appreciated.
Regards
I do not know if this is the best answer but here is what I have for you. Typically I would not do this since it is better to use the UTC time and convert
Here is a example:
value = datetime.datetime.strptime(str(utc_datetime), '%Y-%m-%d %H:%M:%S').replace(tzinfo=pytz.utc)
value = value.astimezone(pytz.timezone("America/Los_Angeles"))
I was unable to use your datetime as the syntax is a bit off so I went ahead and used dateutil.parser to convert it to a datetime object
>>> from dateutil.parser import parse
>>> val = parse('2016-09-15 22:13:03-2:00')
There are other ways to set a datetime object to UTC but I find pytz to be the easiest
>>> import pytz
>>> utc_val = val.replace(tzinfo=pytz.utc)
Here is the output of those two values. From here I grab the delta and subtract it
>>> val, utc_val
(datetime.datetime(2016, 9, 15, 22, 13, 3, tzinfo=tzoffset(None, -7200)), datetime.datetime(2016, 9, 15, 22, 13, 3, tzinfo=<UTC>))
>>>
>>> delta = val - utc_val
I remove the tzinfo since this is a converted datetime value
>>> local_dt = (val - delta).replace(tzinfo=None)
>>> local_dt
datetime.datetime(2016, 9, 15, 20, 13, 3)
>>> str(local_dt)
'2016-09-15 20:13:03'
How do I convert a time to another timezone in Python?
I have found that the best approach is to convert the "moment" of interest to a utc-timezone-aware datetime object (in python, the timezone component is not required for datetime objects).
Then you can use astimezone to convert to the timezone of interest (reference).
from datetime import datetime
import pytz
utcmoment_naive = datetime.utcnow()
utcmoment = utcmoment_naive.replace(tzinfo=pytz.utc)
# print "utcmoment_naive: {0}".format(utcmoment_naive) # python 2
print("utcmoment_naive: {0}".format(utcmoment_naive))
print("utcmoment: {0}".format(utcmoment))
localFormat = "%Y-%m-%d %H:%M:%S"
timezones = ['America/Los_Angeles', 'Europe/Madrid', 'America/Puerto_Rico']
for tz in timezones:
localDatetime = utcmoment.astimezone(pytz.timezone(tz))
print(localDatetime.strftime(localFormat))
# utcmoment_naive: 2017-05-11 17:43:30.802644
# utcmoment: 2017-05-11 17:43:30.802644+00:00
# 2017-05-11 10:43:30
# 2017-05-11 19:43:30
# 2017-05-11 13:43:30
So, with the moment of interest in the local timezone (a time that exists), you convert it to utc like this (reference).
localmoment_naive = datetime.strptime('2013-09-06 14:05:10', localFormat)
localtimezone = pytz.timezone('Australia/Adelaide')
try:
localmoment = localtimezone.localize(localmoment_naive, is_dst=None)
print("Time exists")
utcmoment = localmoment.astimezone(pytz.utc)
except pytz.exceptions.NonExistentTimeError as e:
print("NonExistentTimeError")
Using pytz
from datetime import datetime
from pytz import timezone
fmt = "%Y-%m-%d %H:%M:%S %Z%z"
timezonelist = ['UTC','US/Pacific','Europe/Berlin']
for zone in timezonelist:
now_time = datetime.now(timezone(zone))
print now_time.strftime(fmt)
import datetime
import pytz
def convert_datetime_timezone(dt, tz1, tz2):
tz1 = pytz.timezone(tz1)
tz2 = pytz.timezone(tz2)
dt = datetime.datetime.strptime(dt,"%Y-%m-%d %H:%M:%S")
dt = tz1.localize(dt)
dt = dt.astimezone(tz2)
dt = dt.strftime("%Y-%m-%d %H:%M:%S")
return dt
-
dt: date time string
tz1: initial time zone
tz2: target time zone
-
> convert_datetime_timezone("2017-05-13 14:56:32", "Europe/Berlin", "PST8PDT")
'2017-05-13 05:56:32'
> convert_datetime_timezone("2017-05-13 14:56:32", "Europe/Berlin", "UTC")
'2017-05-13 12:56:32'
-
> pytz.all_timezones[0:10]
['Africa/Abidjan',
'Africa/Accra',
'Africa/Addis_Ababa',
'Africa/Algiers',
'Africa/Asmara',
'Africa/Asmera',
'Africa/Bamako',
'Africa/Bangui',
'Africa/Banjul',
'Africa/Bissau']
Python 3.9 adds the zoneinfo module so now only the the standard library is needed!
>>> from zoneinfo import ZoneInfo
>>> from datetime import datetime
>>> d = datetime(2020, 10, 31, 12, tzinfo=ZoneInfo('America/Los_Angeles'))
>>> d.astimezone(ZoneInfo('Europe/Berlin')) # 12:00 in Cali will be 20:00 in Berlin
datetime.datetime(2020, 10, 31, 20, 0, tzinfo=zoneinfo.ZoneInfo(key='Europe/Berlin'))
Wikipedia list of available time zones
Some functions such as now() and utcnow() return timezone-unaware datetimes, meaning they contain no timezone information. I recommend only requesting timezone-aware values from them using the keyword tz=ZoneInfo('localtime').
If astimezone gets a timezone-unaware input, it will assume it is local time, which can lead to errors:
>>> datetime.utcnow() # UTC -- NOT timezone-aware!!
datetime.datetime(2020, 6, 1, 22, 39, 57, 376479)
>>> datetime.now() # Local time -- NOT timezone-aware!!
datetime.datetime(2020, 6, 2, 0, 39, 57, 376675)
>>> datetime.now(tz=ZoneInfo('localtime')) # timezone-aware
datetime.datetime(2020, 6, 2, 0, 39, 57, 376806, tzinfo=zoneinfo.ZoneInfo(key='localtime'))
>>> datetime.now(tz=ZoneInfo('Europe/Berlin')) # timezone-aware
datetime.datetime(2020, 6, 2, 0, 39, 57, 376937, tzinfo=zoneinfo.ZoneInfo(key='Europe/Berlin'))
>>> datetime.utcnow().astimezone(ZoneInfo('Europe/Berlin')) # WRONG!!
datetime.datetime(2020, 6, 1, 22, 39, 57, 377562, tzinfo=zoneinfo.ZoneInfo(key='Europe/Berlin'))
Windows has no system time zone database, so here an extra package is needed:
pip install tzdata
There is a backport to allow use in Python 3.6 to 3.8:
sudo pip install backports.zoneinfo
Then:
from backports.zoneinfo import ZoneInfo
Time conversion
To convert a time in one timezone to another timezone in Python, you could use datetime.astimezone():
so, below code is to convert the local time to other time zone.
datetime.datetime.today() - return current the local time
datetime.astimezone() - convert the time zone, but we have to pass the time zone.
pytz.timezone('Asia/Kolkata') -passing the time zone to pytz module
Strftime - Convert Datetime to string
# Time conversion from local time
import datetime
import pytz
dt_today = datetime.datetime.today() # Local time
dt_India = dt_today.astimezone(pytz.timezone('Asia/Kolkata'))
dt_London = dt_today.astimezone(pytz.timezone('Europe/London'))
India = (dt_India.strftime('%m/%d/%Y %H:%M'))
London = (dt_London.strftime('%m/%d/%Y %H:%M'))
print("Indian standard time: "+India+" IST")
print("British Summer Time: "+London+" BST")
List all the time zones
import pytz
for tz in pytz.all_timezones:
print(tz)
To convert a time in one timezone to another timezone in Python, you could use datetime.astimezone():
time_in_new_timezone = time_in_old_timezone.astimezone(new_timezone)
Given aware_dt (a datetime object in some timezone), to convert it to other timezones and to print the times in a given time format:
#!/usr/bin/env python3
import pytz # $ pip install pytz
time_format = "%Y-%m-%d %H:%M:%S%z"
tzids = ['Asia/Shanghai', 'Europe/London', 'America/New_York']
for tz in map(pytz.timezone, tzids):
time_in_tz = aware_dt.astimezone(tz)
print(f"{time_in_tz:{time_format}}")
If f"" syntax is unavailable, you could replace it with "".format(**vars())
where you could set aware_dt from the current time in the local timezone:
from datetime import datetime
import tzlocal # $ pip install tzlocal
local_timezone = tzlocal.get_localzone()
aware_dt = datetime.now(local_timezone) # the current time
Or from the input time string in the local timezone:
naive_dt = datetime.strptime(time_string, time_format)
aware_dt = local_timezone.localize(naive_dt, is_dst=None)
where time_string could look like: '2016-11-19 02:21:42'. It corresponds to time_format = '%Y-%m-%d %H:%M:%S'.
is_dst=None forces an exception if the input time string corresponds to a non-existing or ambiguous local time such as during a DST transition. You could also pass is_dst=False, is_dst=True. See links with more details at Python: How do you convert datetime/timestamp from one timezone to another timezone?
For Python timezone conversions, I use the handy table from the PyCon 2012 presentation by Taavi Burns.
Please note: The first part of this answer is or version 1.x of pendulum. See below for a version 2.x answer.
I hope I'm not too late!
The pendulum library excels at this and other date-time calculations.
>>> import pendulum
>>> some_time_zones = ['Europe/Paris', 'Europe/Moscow', 'America/Toronto', 'UTC', 'Canada/Pacific', 'Asia/Macao']
>>> heres_a_time = '1996-03-25 12:03 -0400'
>>> pendulum_time = pendulum.datetime.strptime(heres_a_time, '%Y-%m-%d %H:%M %z')
>>> for tz in some_time_zones:
... tz, pendulum_time.astimezone(tz)
...
('Europe/Paris', <Pendulum [1996-03-25T17:03:00+01:00]>)
('Europe/Moscow', <Pendulum [1996-03-25T19:03:00+03:00]>)
('America/Toronto', <Pendulum [1996-03-25T11:03:00-05:00]>)
('UTC', <Pendulum [1996-03-25T16:03:00+00:00]>)
('Canada/Pacific', <Pendulum [1996-03-25T08:03:00-08:00]>)
('Asia/Macao', <Pendulum [1996-03-26T00:03:00+08:00]>)
Answer lists the names of the time zones that may be used with pendulum. (They're the same as for pytz.)
For version 2:
some_time_zones is a list of the names of the time zones that might be used in a program
heres_a_time is a sample time, complete with a time zone in the form '-0400'
I begin by converting the time to a pendulum time for subsequent processing
now I can show what this time is in each of the time zones in show_time_zones
...
>>> import pendulum
>>> some_time_zones = ['Europe/Paris', 'Europe/Moscow', 'America/Toronto', 'UTC', 'Canada/Pacific', 'Asia/Macao']
>>> heres_a_time = '1996-03-25 12:03 -0400'
>>> pendulum_time = pendulum.from_format('1996-03-25 12:03 -0400', 'YYYY-MM-DD hh:mm ZZ')
>>> for tz in some_time_zones:
... tz, pendulum_time.in_tz(tz)
...
('Europe/Paris', DateTime(1996, 3, 25, 17, 3, 0, tzinfo=Timezone('Europe/Paris')))
('Europe/Moscow', DateTime(1996, 3, 25, 19, 3, 0, tzinfo=Timezone('Europe/Moscow')))
('America/Toronto', DateTime(1996, 3, 25, 11, 3, 0, tzinfo=Timezone('America/Toronto')))
('UTC', DateTime(1996, 3, 25, 16, 3, 0, tzinfo=Timezone('UTC')))
('Canada/Pacific', DateTime(1996, 3, 25, 8, 3, 0, tzinfo=Timezone('Canada/Pacific')))
('Asia/Macao', DateTime(1996, 3, 26, 0, 3, 0, tzinfo=Timezone('Asia/Macao')))
For Python 3.2+ simple-date is a wrapper around pytz that tries to simplify things.
If you have a time then
SimpleDate(time).convert(tz="...")
may do what you want. But timezones are quite complex things, so it can get significantly more complicated - see the the docs.
# Program
import time
import os
os.environ['TZ'] = 'US/Eastern'
time.tzset()
print('US/Eastern in string form:',time.asctime())
os.environ['TZ'] = 'Australia/Melbourne'
time.tzset()
print('Australia/Melbourne in string form:',time.asctime())
os.environ['TZ'] = 'Asia/Kolkata'
time.tzset()
print('Asia/Kolkata in string form:',time.asctime())