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April 2022

4 participants
2 discussions

Trouble to resolve a timezone offset to get correct UTC time
by Pierre 04 Jun '22

04 Jun '22

Hello, I am sorry, I am kind of lost and I would be really grateful to receive some help. Basically, I have a list of timestamps expressed as a strings as below, and I would like them expressed in UTC. But there seems to be a trouble during the offset, which is applied the other way round. The input timestamps look like: 0 'Sat Mar 30 2019 21:00:00 GMT+0100' Adding them in a panda dataframe with to_datetime function, they read then: GC['Time'] = pd.todatetime(my_timestamps) GC['Time'] 0 2019-03-30 21:00:00-01:00 If I further ask: GC['Time'][0] datetime.datetime(2019, 3, 30, 21, 0, tzinfo=tzoffset(None, -3600)) It seems, AFAIK, OK. But then if I want to resolve the offset so as to have time expressed in UTC time, I get: GC['Test'] = pd.to_datetime(GC['Time'],utc=True) 0 2019-03-30 22:00:00+00:00 The offset has bee applied the other way round. Correct timestamp in UTC would be 20:00:00 Please, what should I do to have these timestamps correctly expressed in UTC time? I thank you in advance for your help. I am so sorry to intrude the mailing list with this question, but I am unable to move forward from this point. I thank you again, Bests, Pierre

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strptime and %Z
by Eugene Triguba 24 Apr '22

24 Apr '22

Should `strptime`, when passed a %Z format specifier, parse more than just GMT, UTC, and the local time zone given that we now have the IANA database in the stdlib via PEP 615 since Python 3.9? The regex for the %Z specifier appears to come from TimeRE and always has GMT, UTC, and then the local time zone. >>> from _strptime import TimeRE >>> t = TimeRE() >>> t['Z'] '(?P<Z>cst|gmt|utc|cdt)' >>> from datetime import datetime >>> datetime.strptime('2016-12-04 08:00:00 CST', '%Y-%m-%d %H:%M:%S %Z') datetime.datetime(2016, 12, 4, 8, 0) >>> datetime.strptime('2016-12-04 08:00:00 CDT', '%Y-%m-%d %H:%M:%S %Z') datetime.datetime(2016, 12, 4, 8, 0) >>> datetime.strptime('2016-12-04 08:00:00 UTC', '%Y-%m-%d %H:%M:%S %Z') datetime.datetime(2016, 12, 4, 8, 0) >>> datetime.strptime('2016-12-04 08:00:00 GMT', '%Y-%m-%d %H:%M:%S %Z') datetime.datetime(2016, 12, 4, 8, 0) >>> datetime.strptime('2016-12-04 08:00:00 EST', '%Y-%m-%d %H:%M:%S %Z') Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/home/eugene/src/cpython/Lib/_strptime.py", line 568, in _strptime_datetime tt, fraction, gmtoff_fraction = _strptime(data_string, format) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/home/eugene/src/cpython/Lib/_strptime.py", line 349, in _strptime raise ValueError("time data %r does not match format %r" % ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ValueError: time data '2016-12-04 08:00:00 EST' does not match format '%Y-%m-%d %H:%M:%S %Z' There have been some discussions and issues with regard to this in the past: - https://github.com/python/cpython/issues/66571 - https://github.com/python/cpython/issues/66616 I was interested in taking a look at this, but I wanted to reach out and know if it was something that would be desirable and what others' thoughts were. Thanks, Eugene

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