Python timezone test (with pytz and/or zoneinfo) ¶

Note that: Support for pytz is deprecated in Django 4.0 will be removed in Django 5.0

#!/usr/bin/env python3
import datetime
try:
    import pytz
except:
    pytz = None
try:
    import zoneinfo
except:
    zoneinfo = None


def get_system_tz():
    """
    "Get time zone information of the system in Python?"
    https://stackoverflow.com/questions/1111056/get-time-zone-information-of-the-system-in-python#51296984

    Example:

        print(get_system_tz())
        'CEST'

    """
    return datetime.datetime.now(datetime.timezone.utc).astimezone().tzname()


def is_tz_aware(dt):
    """
    "How to check if a datetime object is localized with pytz?"
    https://stackoverflow.com/questions/5802108/how-to-check-if-a-datetime-object-is-localized-with-pytz#27596917
    """
    return dt.tzinfo is not None and dt.tzinfo.utcoffset(dt) is not None


def print_dt(dt):
    tz_aware = is_tz_aware(dt)
    print("%s ... %s tzaware" % (dt.isoformat(), "is" if tz_aware else "is not"))


print("\nNaive:")
now_naive = datetime.datetime.now()
print_dt(now_naive)

print("\nApply system tz:")
now_tzaware = now_naive.astimezone()
print_dt(now_tzaware)

if pytz:
    print("\nApply specific tz using pytz:")
    now_pacific = now_naive.astimezone(pytz.timezone('US/Pacific'))
    print_dt(now_pacific)

if zoneinfo:
    print("\nApply specific tz using zoneinfo:")
    now_santo_domingo = now_naive.astimezone(zoneinfo.ZoneInfo(key='America/Santo_Domingo'))
    print_dt(now_santo_domingo)

Results:

Naive:
2023-07-25T16:00:26.781075 ... is not tzaware

Apply system tz:
2023-07-25T16:00:26.781075+02:00 ... is tzaware

Apply specific tz using pytz:
2023-07-25T07:00:26.781075-07:00 ... is tzaware

Apply specific tz using zoneinfo:
2023-07-25T10:00:26.781075-04:00 ... is tzaware