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How can I convert date to string in python?

I'm trying to convert it in a simple way using str() but it doesn't work. How can I do that?
import json
import datetime
def lambda_handler(event, context):
lastUpdate="2020-09-17 03:59:21+00:00"
now = datetime.datetime.now().replace(tzinfo=datetime.timezone.utc)
diff = now - lastUpdate
print("Now:" + str(now) + lastUpdate)
Output:
errorMessage": "unsupported operand type(s) for -: 'datetime.datetime' and 'str'",

get the utc timezone and string format as below:
from datetime import datetime, timezone
lastUpdate="2020-09-17 03:59:21+00:00"
now2 = datetime.now(timezone.utc).strftime("%Y%m%d %H:%M:%S")
print("Now:" + str(now2) + lastUpdate)
for the differences, please parse string into two datetime objects and calculate the differences in days.
now3 = datetime.now(timezone.utc)
day = datetime.strptime(lastUpdate, '%Y-%m-%d %H:%M:%S%z')
print("now3= "+ str(now3))
print("day= " + str(day))
diffs = now3 - day
print('Total difference in minutes: ', str(diffs.days))
print("Now:" + str(now3) +" "+ lastUpdate + "Diff= " + str(diffs.days))

The datatype of 'now' is datetime and of 'lastUpdate' is str, you cannot get difference between different datatypes. Convert lastUpdate to datetime format first.
import json
from datetime import datetime, timezone
from dateutil import parser
def lambda_handler(event, context):
lastUpdate="2020-09-17 03:59:21+00:00"
lastUpdate = parser.parse("2020-09-17 03:59:21+00:00")
now = datetime.now(timezone.utc)
diff = now - lastUpdate
print("Now:" + str(now) + str(lastUpdate))

strftime-and-strptime-behavior
strftime-and-strptime-format-codes
from datetime import datetime
lastUpdate = "2020-09-17 03:59:21+00:00"
dt: datetime = datetime.strptime(lastUpdate, "%Y-%m-%d %H:%M:%S%z")
print(repr(dt))
# datetime.datetime(2020, 9, 17, 3, 59, 21, tzinfo=datetime.timezone.utc)
dt_str = dt.strftime("%Y-%m-%d %H:%M:%S")
print(repr(dt_str))
# '2020-09-17 03:59:21'

python convert PST time to UTC isoformat

ex:
I have a date string
2018-02-17 16:15:36.519 PST
How do i convert into isoformat in UTC like below
2018-02-18T00:15:36.519Z
I tried this
from dateutil.parser import parse
d1='2018-02-17 16:15:36.519 PST'
print parse(d1)
it prints like this. How do i convert it to UTC with Z at the end.
2018-02-17 16:15:36.519000-08:00
EDIT
using python 2.7.
import dateutil
import pytz
from dateutil.parser import parse
d1='2018-02-17 16:15:36.519 PST'
d2=dateutil.parser.parse(d1)
d2.replace(tzinfo=pytz.utc) - d2.utcoffset()
d3=(d2.replace(tzinfo=pytz.utc) - d2.utcoffset()).isoformat()
print d3
then formatting with Z as suggested

To parse a time string with a timezone abbreviation (PST) into a timezone-aware datetime object:
import dateparser # pip install dateparser
pst_dt = dateparser.parse('2018-02-17 16:15:36.519 PST')
# -> datetime.datetime(2018, 2, 17, 16, 15, 36, 519000, tzinfo=<StaticTzInfo 'PST'>)
To convert the time to UTC timezone:
import datetime as DT
utc_dt = pst_dt.astimezone(DT.timezone.utc)
# -> datetime.datetime(2018, 2, 18, 0, 15, 36, 519000, tzinfo=datetime.timezone.utc)
To print it in the desired format:
print(utc_dt.isoformat()) # -> 2018-02-18T00:15:36.519000+00:00
print(utc_dt.strftime('%Y-%m-%dT%H:%M:%S.%fZ')) # -> 2018-02-18T00:15:36.519000Z
On Python 2.7 there is no DT.timezone.utc:
utc_naive = psd_dt.replace(tzinfo=None) - psd_dt.utcoffset()
print utc_naive.strftime('%Y-%m-%dT%H:%M:%S.%fZ')
# -> 2018-02-18T00:15:36.519000Z
Note: in the general case the timezone abbreviation (such as PST) may be ambiguous. See Parsing date/time string with timezone abbreviated name in Python?
In your specific case, the time string corresponds to unique UTC time:
>>> from collections import defaultdict
>>> import datetime as DT
>>> import pytz
>>> naive_dt, tzabbr = DT.datetime(2018, 2, 17, 16, 15, 36, 519000), 'PST'
>>> utc_times = defaultdict(list)
>>> for zone in pytz.all_timezones:
... dt = pytz.timezone(zone).localize(naive_dt, is_dst=None)
... if dt.tzname() == tzabbr: # same timezone abbreviation
... utc_times[dt.astimezone(pytz.utc)].append(zone)
>>> for utc_dt, timezones in utc_times.items():
... print(f'{utc_dt:%c %Z}', *timezones, sep='\n\t')
Sun Feb 18 00:15:36 2018 UTC
America/Dawson
America/Ensenada
America/Los_Angeles
America/Santa_Isabel
America/Tijuana
America/Vancouver
America/Whitehorse
Canada/Pacific
Canada/Yukon
Mexico/BajaNorte
PST8PDT
US/Pacific
US/Pacific-New
See linux convert time(for different timezones) to UTC

This is a demo code from python2.7, FYI, thanks!
from datetime import datetime
from pytz import utc, timezone
def get_current_pst_time():
print('------------(1) Current time to PST time----------------')
local_time = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
utc_time = datetime.now(tz=utc).strftime('%Y-%m-%d %H:%M:%S')
pst_time = datetime.now(tz=utc).astimezone(timezone('US/Pacific')).strftime('%Y-%m-%d %H:%M:%S')
is_summary_time = bool(datetime.now(tz=utc).astimezone(timezone('US/Pacific')).dst())
print('is it a summary time? %s.' % is_summary_time)
print('local time is %s.' % local_time)
print('utc time is %s.' % utc_time)
print('pst time is %s.' % pst_time)
def convert_pst_time_to_utc_time(pst_time_str):
print('------------(2) PST time to UTC time----------------')
print('pst time is %s.' % pst_time_str)
temp_time = datetime.strptime(pst_time_str, '%Y-%m-%d %H:%M:%S')
pacific_timezone = timezone('US/Pacific')
pst_time = pacific_timezone.localize(temp_time, is_dst=None)
assert pst_time.tzinfo is not None
assert pst_time.tzinfo.utcoffset(pst_time) is not None
is_summary_time = bool(pst_time.dst())
print('is it a summary time? %s.' % is_summary_time)
utc_time = pst_time.astimezone(timezone('utc'))
print('utc time is %s.' % utc_time.strftime('%Y-%m-%d %H:%M:%S'))
def convert_utc_time_to_pst_time(utc_time_str):
print('------------(3) UTC time to PST time----------------')
print('utc time is %s.' % utc_time_str)
temp_time = datetime.strptime(utc_time_str, '%Y-%m-%d %H:%M:%S')
utc_timezone = timezone('utc')
utc_time = utc_timezone.localize(temp_time, is_dst=None)
assert utc_time.tzinfo is not None
assert utc_time.tzinfo.utcoffset(utc_time) is not None
pst_time = utc_time.astimezone(timezone('US/Pacific'))
is_summary_time = bool(pst_time.dst())
print('is it a summary time? %s.' % is_summary_time)
print('pst time is %s.' % pst_time.strftime('%Y-%m-%d %H:%M:%S'))
if __name__ == '__main__':
get_current_pst_time()
convert_pst_time_to_utc_time('2019-12-03 02:00:00')
convert_pst_time_to_utc_time('2020-07-03 02:00:00')
convert_utc_time_to_pst_time('2019-12-03 10:00:00')
convert_utc_time_to_pst_time('2020-07-03 09:00:00')

getting incorrect utc to local time for timezone given

If I run this url : https://api.sunrise-sunset.org/json?lat=12.98&lng=77.61&date=2017-08-26
I get sunrise time: "12:38:14 AM"
and this is UTC time, if I convert it to given timezone using :
from datetime import datetime
import pytz
from dateutil import tz
def convertUTCtoLocal(date, utcTime, timezone):
""" converts UTC time to given timezone
"""
to_zone = pytz.timezone(timezone)
from_zone = _tz.gettz('UTC')
utc = _datetime.strptime('%s %s' % (date, utcTime), '%Y-%m-%d %H:%M:%S')
utc = utc.replace(tzinfo=from_zone)
local = utc.astimezone(to_zone)
return str(local.time())
but this returns 18:08:16 which is evening time , so what am I doing wrong here.
given timzone is Asia/Kolkata
Example:
>>> from datetime import datetime
>>> from dateutil import tz
>>> from_zone = tz.gettz('UTC')
>>> to_zone = tz.gettz('Asia/Kolkata')
>>> utc = datetime.strptime('2011-01-21 02:37:21', '%Y-%m-%d %H:%M:%S')
>>> utcTime = "12:38:16" ## from json URL we get AM/PM but I remove it.
>>> utc = datetime.strptime('2017-08-26 {}'.format(utcTime), '%Y-%m-%d %H:%M:%S')
>>> utc
datetime.datetime(2017, 8, 26, 12, 38, 16)
>>> utc = utc.replace(tzinfo=from_zone)
>>> central = utc.astimezone(to_zone)
>>> central
datetime.datetime(2017, 8, 26, 18, 8, 16, tzinfo=tzfile('/usr/share/zoneinfo/Asia/Kolkata'))

The problem was that you had "12:38:16 AM" which is actual "00:38:16" so you can't just strip "AM". I changed your function so it will work with "AM" and "PM" hours, just don't strip "AM" and "PM" before using the function:
import pytz
from _datetime import datetime
from dateutil import tz
def convertUTCtoLocal(date, utcTime, timezone):
""" converts UTC time to given timezone
"""
to_zone = pytz.timezone(timezone)
from_zone = tz.gettz('UTC')
## for formating with AM and PM hours in strptime you need to add
## %p at the end, also instead of %H you need to use %I
utc = datetime.strptime('%s %s' % (date, utcTime), '%Y-%m-%d %I:%M:%S %p')
utc = utc.replace(tzinfo=from_zone)
local = utc.astimezone(to_zone)
return str(local.time())
date = '2017-08-26'
utcTime = '12:38:14 AM' ## Don't strip AM or PM
timezone = 'Asia/Kolkata'
x = convertUTCtoLocal(date, utcTime, timezone)
print(x)
Also, you can see working example here.

Get tz offset from string

I have a date which is in local time:
date: "2013-12-02 22:00:00"
and another value the tz:
timezone_offset: "GMT-0800"
If I : dateutil.parser.parse(date).isoformat() I will get:
"2013-12-02T22:00:00+0000"
I want to implement the date in ISO format with the tz info and get a result of:
"2013-12-02T22:00:00-0800"
Something close to: parse(date,tzinfos=??).isoformat() ? How can I get the tzinfo from the string timezone_offset ?

>>> from dateutil.parser import parse
>>> dt = parse("2013-12-02 22:00:00" + "GMT+0800")
>>> dt.isoformat()
'2013-12-02T22:00:00-08:00'
Note: the sign is reversed.
You could also do it using only stdlib:
>>> from datetime import datetime
>>> dt = datetime.strptime("2013-12-02 22:00:00", "%Y-%m-%d %H:%M:%S")
>>> dt = dt.replace(tzinfo=FixedOffset(-8*60, "GMT+0800"))
>>> dt.isoformat()
'2013-12-02T22:00:00-08:00'
where FixedOffset is taken from datetime docs:
from datetime import tzinfo, timedelta
class FixedOffset(tzinfo):
"""Fixed offset in minutes east from UTC."""
def __init__(self, offset, name):
self.__offset = timedelta(minutes = offset)
self.__name = name
def utcoffset(self, dt):
return self.__offset
def tzname(self, dt):
return self.__name
def dst(self, dt):
return timedelta(0)
Here's the same using pytz module:
>>> from datetime import datetime
>>> import pytz
>>> dt = datetime.strptime("2013-12-02 22:00:00", "%Y-%m-%d %H:%M:%S")
>>> dt = pytz.timezone('Etc/GMT+8').localize(dt)
>>> dt.isoformat()
'2013-12-02T22:00:00-08:00'

Here are two approaches you could use:
>>> import datetime
>>> dtnow = datetime.datetime.now();dtutcnow = datetime.datetime.utcnow()
>>> dtnow
datetime.datetime(2013, 11, 12, 9, 10, 48, 404000)
>>> dtutcnow
datetime.datetime(2013, 11, 12, 15, 10, 48, 404000)
>>> delta = dtnow - dtutcnow
>>> delta
datetime.timedelta(-1, 64800)
>>> hh,mm = divmod((delta.days * 24*60*60 + delta.seconds + 30) // 60, 60)
>>> hh,mm
(-6, 0)
>>> "%s%+02d:%02d" % (dtnow.isoformat(), hh, mm)
'2013-11-12T09:10:48.404000-6:00'
Or this:
>>> import datetime, pytz # 3rd Party
>>> datetime.datetime.now(pytz.timezone('US/Central')).strftime('%Y-%m-%dT%H:%M:%S.%f%z')
'2013-11-12T09:15:20.688000-0600'
>>>
The main advantage of the second method is it makes your time string 'timezone aware'. From the docs:
There are two kinds of date and time objects: “naive” and “aware”.
This distinction refers to whether the object has any notion of time
zone, daylight saving time, or other kind of algorithmic or political
time adjustment. Whether a naive datetime object represents
Coordinated Universal Time (UTC), local time, or time in some other
timezone is purely up to the program, just like it’s up to the program
whether a particular number represents metres, miles, or mass. Naive
datetime objects are easy to understand and to work with, at the cost
of ignoring some aspects of reality.
Hope this helps!

how to convert string to datetime.timedelta()?

how can i convert my string of date to a datetime.timedelta() in Python?
I have this code :
import datetime
date_select = '2011-12-1'
delta = datetime.timedelta(days=1)
target_date = date_select + delta
print target_date
thanks in advance ...

You wouldn't convert date_select to a timedelta, instead, you need a datetime object, which can be added to a timedelta to produce an updated datetime object:
from datetime import datetime, timedelta
date_select = datetime.strptime('2011-12-1', '%Y-%m-%d')
delta = timedelta(days=1)
target_date = date_select + delta
print target_date
Or, if you prefer, without the fancy from ... import ... import line:
import datetime # <- LOOK HERE, same as in your example
date_select = datetime.datetime.strptime('2011-12-1', '%Y-%m-%d')
delta = datetime.timedelta(days=1)
target_date = date_select + delta
print target_date

You use strptime to do this.
from datetime import datetime
target_date = datetime.strptime(date_select, '%Y-%m-%d')

from datetime import datetime, timedelta
date_select = '2011-12-1'
new_data = datetime.strptime(date_select, '%Y-%m-%d')
delta = timedelta(days=1)
target_date = date_select + delta
print target_date
You will get 2011-12-02 00:00:00; to strip off the '00:00:00' and get only the date, just add .date() to target_date
print target_date.date()
This should give you the only the date = 2011-12-02