diff options
Diffstat (limited to 'Doc/library/datetime.rst')
| -rw-r--r-- | Doc/library/datetime.rst | 111 |
1 files changed, 60 insertions, 51 deletions
diff --git a/Doc/library/datetime.rst b/Doc/library/datetime.rst index 00cfaeb66f..15b500f770 100644 --- a/Doc/library/datetime.rst +++ b/Doc/library/datetime.rst @@ -1348,56 +1348,64 @@ Examples of working with datetime objects: Using datetime with tzinfo: - >>> from datetime import timedelta, datetime, tzinfo - >>> class GMT1(tzinfo): + >>> from datetime import timedelta, datetime, tzinfo, timezone + >>> class KabulTz(tzinfo): + ... # Kabul used +4 until 1945, when they moved to +4:30 + ... UTC_MOVE_DATE = datetime(1944, 12, 31, 20, tzinfo=timezone.utc) ... def utcoffset(self, dt): - ... return timedelta(hours=1) + self.dst(dt) - ... def dst(self, dt): - ... # DST starts last Sunday in March - ... d = datetime(dt.year, 4, 1) # ends last Sunday in October - ... self.dston = d - timedelta(days=d.weekday() + 1) - ... d = datetime(dt.year, 11, 1) - ... self.dstoff = d - timedelta(days=d.weekday() + 1) - ... if self.dston <= dt.replace(tzinfo=None) < self.dstoff: - ... return timedelta(hours=1) + ... if dt.year < 1945: + ... return timedelta(hours=4) + ... elif (1945, 1, 1, 0, 0) <= dt.timetuple()[:5] < (1945, 1, 1, 0, 30): + ... # If dt falls in the imaginary range, use fold to decide how + ... # to resolve. See PEP495 + ... return timedelta(hours=4, minutes=(30 if dt.fold else 0)) ... else: - ... return timedelta(0) - ... def tzname(self,dt): - ... return "GMT +1" + ... return timedelta(hours=4, minutes=30) + ... + ... def fromutc(self, dt): + ... # A custom implementation is required for fromutc as + ... # the input to this function is a datetime with utc values + ... # but with a tzinfo set to self + ... # See datetime.astimezone or fromtimestamp + ... + ... # Follow same validations as in datetime.tzinfo + ... if not isinstance(dt, datetime): + ... raise TypeError("fromutc() requires a datetime argument") + ... if dt.tzinfo is not self: + ... raise ValueError("dt.tzinfo is not self") + ... + ... if dt.replace(tzinfo=timezone.utc) >= self.UTC_MOVE_DATE: + ... return dt + timedelta(hours=4, minutes=30) + ... else: + ... return dt + timedelta(hours=4) ... - >>> class GMT2(tzinfo): - ... def utcoffset(self, dt): - ... return timedelta(hours=2) + self.dst(dt) ... def dst(self, dt): - ... d = datetime(dt.year, 4, 1) - ... self.dston = d - timedelta(days=d.weekday() + 1) - ... d = datetime(dt.year, 11, 1) - ... self.dstoff = d - timedelta(days=d.weekday() + 1) - ... if self.dston <= dt.replace(tzinfo=None) < self.dstoff: - ... return timedelta(hours=1) + ... return timedelta(0) + ... + ... def tzname(self, dt): + ... if dt >= self.UTC_MOVE_DATE: + ... return "+04:30" ... else: - ... return timedelta(0) - ... def tzname(self,dt): - ... return "GMT +2" + ... return "+04" ... - >>> gmt1 = GMT1() - >>> # Daylight Saving Time - >>> dt1 = datetime(2006, 11, 21, 16, 30, tzinfo=gmt1) - >>> dt1.dst() - datetime.timedelta(0) - >>> dt1.utcoffset() - datetime.timedelta(seconds=3600) - >>> dt2 = datetime(2006, 6, 14, 13, 0, tzinfo=gmt1) - >>> dt2.dst() - datetime.timedelta(seconds=3600) - >>> dt2.utcoffset() - datetime.timedelta(seconds=7200) + ... def __repr__(self): + ... return f"{self.__class__.__name__}()" + ... + >>> tz1 = KabulTz() + >>> # Datetime before the change + >>> dt1 = datetime(1900, 11, 21, 16, 30, tzinfo=tz1) + >>> print(dt1.utcoffset()) + 4:00:00 + >>> # Datetime after the change + >>> dt2 = datetime(2006, 6, 14, 13, 0, tzinfo=tz1) + >>> print(dt2.utcoffset()) + 4:30:00 >>> # Convert datetime to another time zone - >>> dt3 = dt2.astimezone(GMT2()) - >>> dt3 # doctest: +ELLIPSIS - datetime.datetime(2006, 6, 14, 14, 0, tzinfo=<GMT2 object at 0x...>) - >>> dt2 # doctest: +ELLIPSIS - datetime.datetime(2006, 6, 14, 13, 0, tzinfo=<GMT1 object at 0x...>) + >>> dt3 = dt2.astimezone(timezone.utc) + >>> dt3 + datetime.datetime(2006, 6, 14, 8, 30, tzinfo=datetime.timezone.utc) + >>> dt2 + datetime.datetime(2006, 6, 14, 13, 0, tzinfo=KabulTz()) >>> dt2.utctimetuple() == dt3.utctimetuple() True @@ -1639,26 +1647,27 @@ Instance methods: Example: >>> from datetime import time, tzinfo, timedelta - >>> class GMT1(tzinfo): + >>> class TZ1(tzinfo): ... def utcoffset(self, dt): ... return timedelta(hours=1) ... def dst(self, dt): ... return timedelta(0) ... def tzname(self,dt): - ... return "Europe/Prague" + ... return "+01:00" + ... def __repr__(self): + ... return f"{self.__class__.__name__}()" ... - >>> t = time(12, 10, 30, tzinfo=GMT1()) - >>> t # doctest: +ELLIPSIS - datetime.time(12, 10, 30, tzinfo=<GMT1 object at 0x...>) - >>> gmt = GMT1() + >>> t = time(12, 10, 30, tzinfo=TZ1()) + >>> t + datetime.time(12, 10, 30, tzinfo=TZ1()) >>> t.isoformat() '12:10:30+01:00' >>> t.dst() datetime.timedelta(0) >>> t.tzname() - 'Europe/Prague' + '+01:00' >>> t.strftime("%H:%M:%S %Z") - '12:10:30 Europe/Prague' + '12:10:30 +01:00' >>> 'The {} is {:%H:%M}.'.format("time", t) 'The time is 12:10.' |