How can I convert a time string with region/city timezone format to UTC using pytz and datetime libraries?

I'm working with times formatted as Tue, 27 Dec 2022 21:01:54 Region/City, the part except Region/City can be formatted in any number of ways like 27-Dec-2022 or 27 Dec 2022.

I want to convert this string to UTC format ie. DAY, DD MM YYYY HH:MM:SS GMT

I'm using the pytz and datetime library for this and I'm not sure how to proceed after this:

import datetime as dt
import pytz

def convert_timezone(date_str):
    if any((match_tz := tz) in date_str for tz in pytz.all_timezones):
        date_str_notz = date_str.replace(match_tz, "")
        print(date_str_notz)
        for date_frmt in [
            "%a, %d %b %Y %H:%M:%S",
            "%a, %d-%b-%Y %H:%M:%S",
        ]:
            naive_time = dt.datetime.strptime(date_str_notz, date_frmt)

        local_tz = pytz.timezone(match_tz)
        local_time = local_tz.localize(naive_time, is_dst=None)
        utc_time = local_time.astimezone(pytz.utc)
        return(utc_time)

result=convert_timezone("Tue, 27 Dec 2022 21:01:54 Asia/Kolkata")
print(result)

But this gives the error:

Tue, 27 Dec 2022 21:01:54 
Traceback (most recent call last):
  File "/home/user/Git/github/data/url.py", line 21, in <module>
    result=convert_timezone("Tue, 27 Dec 2022 21:01:54 Asia/Kolkata")
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/Git/github/data/url.py", line 13, in convert_timezone
    naive_time = dt.datetime.strptime(date_str_notz, date_frmt)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/_strptime.py", line 568, in _strptime_datetime
    tt, fraction, gmtoff_fraction = _strptime(data_string, format)
                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/_strptime.py", line 352, in _strptime
    raise ValueError("unconverted data remains: %s" %
ValueError: unconverted data remains:  

However this seems to work fine:

>>> datetime.datetime.strptime('Tue, 27 Dec 2022 21:01:54', '%a, %d %b %Y %H:%M:%S')
datetime.datetime(2022, 12, 27, 21, 1, 54)
>>> 

From the code provided by you I noticed you are separating the time zone and and date string. While you are separating them using replace(match_tz,"") method you are leaving a extra space after to the date_str string. This causes the datetime.strptimee() function to fail as it can't find the specified format. To overcome this use strip() method at the end.

    date_str_notz = date_str.replace(match_tz, "").strip()

Your code flow:

1. date_str = "Tue, 27 Dec 2022 21:01:54 Asia/Kolkata"
2. After replace() function date_str_notz = "Tue, 27 Dec 2022 21:01:54 "

My code flow:

1. date_str = "Tue, 27 Dec 2022 21:01:54 Asia/Kolkata"
2. After replace() function date_str_notz = "Tue, 27 Dec 2022 21:01:54"