Parsing GST timezone with datetime.strptime - python

I am trying to parse a str as a datetime.datetime object. However, I am unable to achieve this because the timezone is GST.
import datetime
s_dt = 'Mon Jul 01 17:17:37 UTC'
datetime.datetime.strptime(s_dt, '%a %b %d %H:%M:%S %Z')
# datetime.datetime(1900, 7, 1, 17, 17, 37)
s_dt = 'Mon Jul 01 17:17:37 GST'
datetime.datetime.strptime(s_dt, '%a %b %d %H:%M:%S %Z')
# ValueError: time data 'Mon Jul 01 17:17:37 GST' does not match format '%a %b %d %H:%M:%S %Z'
How can I fix this?

There are two ways to deal with this:-
Replace the GST in the string, to UTC
Replace the GST in the string, to UTC with proper time conversion (decreasing the time in UTC by 4 hours, as time GST is +4 hours from UTC).
METHOD 1:-
s_dt = 'Mon Jul 01 17:17:37 GST'.replace("GST", "UTC")
datetime.datetime.strptime(s_dt, '%a %b %d %H:%M:%S %Z')
METHOD 2:-
# replacing GST to UTC in original string
s_dt = 'Mon Jul 01 17:17:37 GST'.replace("GST", "UTC")
# getting the hours from the string
s_dt_obj = int(s_dt.split(":")[0][-2:])
# substracting 4 from the hours (in order to create UTC equivalent of GST time)
s_dt_obj = str((s_dt_obj - 4) % 24)
# putting everything back to a string
s_dt_obj = f"{s_dt.split(':')[0][:-2]}{s_dt_obj}:{s_dt.split(':')[1]}:{s_dt.split(':')[2]}"
# creating datetime object out of our newly created string
datetime.datetime.strptime(s_dt_obj, '%a %b %d %H:%M:%S %Z')
# datetime.datetime(1900, 7, 1, 13, 17, 37)

Related

How to convert timezone in number to UTC?

I have some random dates with different timezones, they are in formats like this "07 Mar 2022 13:52:00 -0300", or they could be like this: "07 Mar 2022 11:12:00 -0700". I don't know which timezone exactly they will be coming from. How can I convert all of them to UTC time "0000Z"?
You can use standard module datetime for this.
Function strptime() (string parsing time) can convert string to object datetime using matching pattern. For your examples works pattern '%d %b %Y %H:%M:%S %z'
Next you can use .astimezone(datetime.timezone.utc) to convert to UTC.
And later you can format string with strftime() (string formatting time) using again pattern '%d %b %Y %H:%M:%S %z' (or you can skip %z)
Minimal working code:
import datetime
data = [
"07 Mar 2022 13:52:00 -0300",
"07 Mar 2022 11:12:00 -0700",
]
for item in data:
print('before str:', item)
dt = datetime.datetime.strptime(item, '%d %b %Y %H:%M:%S %z')
print('before dt :', dt)
dt = dt.astimezone(datetime.timezone.utc)
print('after dt :', dt)
print('after str:', dt.strftime('%d %b %Y %H:%M:%S %z'))
print('---')
Result:
before str: 07 Mar 2022 13:52:00 -0300
before dt : 2022-03-07 13:52:00-03:00
after dt : 2022-03-07 16:52:00+00:00
after str: 07 Mar 2022 16:52:00 +0000
---
before str: 07 Mar 2022 11:12:00 -0700
before dt : 2022-03-07 11:12:00-07:00
after dt : 2022-03-07 18:12:00+00:00
after str: 07 Mar 2022 18:12:00 +0000
---
I would suggest to import datetime, then use the following method to convert your time stamps into datetime objects (where str is the time stamp as a string): time_stamp = datetime.strptime(str, "%d %b %Y") (where the parameter after str gives information on the formatting; for details see here: https://www.programiz.com/python-programming/datetime/strptime).
After that, you can use datetime.astimezone() to convert this into another time zone.

strptime() gives ValueError: time data 'AM CDT' does not match format '%p %Z'

I have a str that I want to convert to a datetime. This str is this: 'Thursday, September 9, 2021 at 11:50 AM CDT. I am using the datetime.strptime() function, but it seems like the AM or time zone is not being recognized.
When I use the code
time = 'Thursday, September 9, 2021 at 11:50 AM CDT'
time = datetime.strptime(time, '%A, %B %d, %Y at %I:%M %p %Z')
I get the following:
ValueError: time data 'Thursday, September 9, 2021 at 11:50 AM CDT' does not match format '%A, %B %d, %Y at %I:%M %p %Z:%M %p %Z'
I've been able to convert the first part up until the %p %Z part, at which I get the following error:
ValueError: time data 'AM CDT' does not match format '%p %Z'
Any ideas on how dt.strptime() can recognize AM/PM and the time zone correctly?
Not sure of the best approach, but since Python 3.9 you can use the ZoneInfo module for this:
from datetime import datetime
from zoneinfo import ZoneInfo
CDT = ZoneInfo('CST6CDT')
# or alternatively:
# CDT = ZoneInfo('US/Central')
time = 'Thursday, September 9, 2021 at 1:50 PM'
time = datetime.strptime(time, '%A, %B %d, %Y at %I:%M %p')
time = time.replace(tzinfo=CDT)
print(time) # 2021-09-09 13:50:00-05:00
#MrFuppes made a good point about an ambiguity between the CST6EDT and US/Central zones. However, when I tried a quick test in DST and outside of DST, I couldn't see any noticeable difference, as the time zone seemed to adjust automatically - which indicates that either of those zone values appear to be DST- aware (unless I'm missing something of course).
I added an example below:
from datetime import datetime
from zoneinfo import ZoneInfo
# CDT = ZoneInfo('CST6CDT')
CDT = ZoneInfo('US/Central')
# Note: DST in 2021, ends on November 7th
time_dst = 'Saturday, November 6, 2021 at 1:50 PM'
time_st = 'Monday, November 8, 2021 at 1:50 PM'
time_dst = datetime.strptime(time_dst, '%A, %B %d, %Y at %I:%M %p')
time_dst = time_dst.replace(tzinfo=CDT)
time_st = datetime.strptime(time_st, '%A, %B %d, %Y at %I:%M %p')
time_st = time_st.replace(tzinfo=CDT)
print('DST: ', time_dst)
print('ST: ', time_st)
Output appears to be the same despite which ZoneInfo object is used:
DST: 2021-11-06 13:50:00-05:00
ST: 2021-11-08 13:50:00-06:00

How to convert UTC/extended format to datetime in Python

I want to convert datetime in %Y-%m-%d,
so from Sat, 17 Apr 2021 16:17:00 +0100 to 17-04-2021
def convertDatetime(data):
test_datetime = data
data_new_format = datetime.datetime.strptime(test_datetime,'%- %Y %M %d')
print(data_new_format)
convertDatetime("Sat, 17 Apr 2021 16:17:00 +0100")
but it say me: '-' is a bad directive in format '%- %Y %M %d'
The format you specify '%- %Y %M %d' (1) contains an incorrect specifier - as the error says, and also (2) completely does not match the data you want to convert. The format you pass to strptime() must match the way the data looks, not the way you want it to look.
>>> data="Sat, 17 Apr 2021 16:17:00 +0100"
>>> format = "%a, %d %b %Y %H:%M:%S %z"
>>> datetime.datetime.strptime(data, format)
datetime.datetime(2021, 4, 17, 16, 17, tzinfo=datetime.timezone(datetime.timedelta(seconds=3600)))
To reformat the datetime the way you want, you need a second call, to strftime():
>>> datetime.datetime.strptime(data, format).strftime("%Y-%m-%d")
'2021-04-17'

Python datetime strptime() does not match format

I get the following error in which you can see the time data and the format I am using
time data '20:07:35 EEDT Wed Mar 31 2021' does not match format '%H:%M:%S %Z %a %b %d %Y'
I used the directives from here and I see that the format matches the description of each directive.
Can you see what is the issue here?
import datetime
time = '20:07:35 EEDT Wed Mar 31 2021'
time = time.replace('EEDT', '+0300')
datetime.datetime.strptime(time, '%H:%M:%S %z %a %b %d %Y')
you can map the abbreviated time zone to a IANA time zone name by dateutil's parser:
import dateutil
s = '20:07:35 EEDT Wed Mar 31 2021'
tzmapping = {"EEDT": dateutil.tz.gettz('Europe/Athens'),
"EEST": dateutil.tz.gettz('Europe/Athens')} # add more if needed...
dtobj = dateutil.parser.parse(s, tzinfos=tzmapping)
that will give you
dtobj
# >>> datetime.datetime(2021, 3, 31, 20, 7, 35, tzinfo=tzfile('Europe/Athens'))
dtobj.utcoffset()
# >>> datetime.timedelta(seconds=10800) # UTC+3
Note that timedelta arithmetic works correctly, i.e. includes DST changes:
from datetime import timedelta
dtobj -= timedelta(7) # DST change: dtobj is now EEST, UTC+2
dtobj.utcoffset()
# >>> datetime.timedelta(seconds=7200)
Problem is with EEDT. If you ignore EEDT(quickfix, not ideal), then your code may look like:
text = '20:07:35 EEDT Wed Mar 31 2021';
fmt = '%H:%M:%S EEDT %a %b %d %Y';
datetime.strptime(text, fmt)
--edit--
parsing datetime with timezone is difficult to pure datetime module. I'm not big expert, but pytz or python-datetutil should be good choice, according to this page: https://medium.com/#nqbao/python-timezone-and-daylight-savings-e511a0093d0
For those who are interested in different approach for similar, like GMT and BST or EEST and EEDT, it can be represented like this:
import datetime
try:
Time1 = datetime.datetime.strptime(DropTm,"%a %b %d %H:%M:%S GMT %Y")
except:
Time1 = datetime.datetime.strptime(DropTm,"%a %b %d %H:%M:%S BST %Y")
In your situation it will be:
import datetime
try:
Time1 = datetime.datetime.strptime(SomeValue,"%H:%M:%S EEDT %a %b %d %Y")
except:
Time1 = datetime.datetime.strptime(SomeValue,"%H:%M:%S EEST %a %b %d %Y")
Where is "SomeValue" your data!!
It did worked for me and do not need any other libraries! Good Luck with coding!!!

How to fix ValueError time date does not match format when converting from string to datetime

Im trying to convert a string to datetime and keep getting the error: ValueError: time data 'Mon, 22 Apr 2019 17:04:38 +0200 (CEST)' does not match format '%a, %d %b %Y %H:%M:%S %z %Z'
from datetime import datetime
s = "Mon, 22 Apr 2019 17:04:38 +0200 (CEST)"
d = datetime.strptime(s, '%a, %d %b %Y %H:%M:%S %z %Z')
What am i missing?
%Z is generally used for converting into string format. In any case, it is the offset, not the name of the time zone.
The rest of your code is valid, however:
s = "Mon, 22 Apr 2019 17:04:38 +0200"
d = datetime.strptime(s, '%a, %d %b %Y %H:%M:%S %z')
datetime only comes with the ability to parse UTC and whatever local time zone is listed in time.tzname. It can't match (CEST) because it doesn't know what timezone that is (It would also be redundant because you defined the timezone using the offset +0200).
You will need to implement your own (CEST) using datetime.tzinfo or by importing an external library like pytz or pendulum in order to parse (CEST) from a string into a datetime.timezone.
Also, don't forget to include parenthesis() in your match string.
This code passes, however, I do not know what happens to 'CEST' once it is converted into the string.
from datetime import datetime
tz = 'CEST'
s = "Mon, 22 Apr 2019 17:04:38 +0200 " + tz
d = datetime.strptime(s, '%a, %d %b %Y %H:%M:%S %z ' + tz)

Categories