Python datetime.datetime.tzinfo() Examples

def _assert_tzawareness_compat(self, other):
        # adapted from _Timestamp._assert_tzawareness_compat
        other_tz = getattr(other, 'tzinfo', None)
        if is_datetime64tz_dtype(other):
            # Get tzinfo from Series dtype
            other_tz = other.dtype.tz
        if other is NaT:
            # pd.NaT quacks both aware and naive
            pass
        elif self.tz is None:
            if other_tz is not None:
                raise TypeError('Cannot compare tz-naive and tz-aware '
                                'datetime-like objects.')
        elif other_tz is None:
            raise TypeError('Cannot compare tz-naive and tz-aware '
                            'datetime-like objects')

    # -----------------------------------------------------------------
    # Arithmetic Methods 

def is_ambiguous(self, dt):
        """
        Whether or not the "wall time" of a given datetime is ambiguous in this
        zone.

        :param dt:
            A :py:class:`datetime.datetime`, naive or time zone aware.


        :return:
            Returns ``True`` if ambiguous, ``False`` otherwise.

        .. versionadded:: 2.6.0
        """

        dt = dt.replace(tzinfo=self)

        wall_0 = enfold(dt, fold=0)
        wall_1 = enfold(dt, fold=1)

        same_offset = wall_0.utcoffset() == wall_1.utcoffset()
        same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)

        return same_dt and not same_offset 

def _fold_status(self, dt_utc, dt_wall):
        """
        Determine the fold status of a "wall" datetime, given a representation
        of the same datetime as a (naive) UTC datetime. This is calculated based
        on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
        datetimes, and that this offset is the actual number of hours separating
        ``dt_utc`` and ``dt_wall``.

        :param dt_utc:
            Representation of the datetime as UTC

        :param dt_wall:
            Representation of the datetime as "wall time". This parameter must
            either have a `fold` attribute or have a fold-naive
            :class:`datetime.tzinfo` attached, otherwise the calculation may
            fail.
        """
        if self.is_ambiguous(dt_wall):
            delta_wall = dt_wall - dt_utc
            _fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
        else:
            _fold = 0

        return _fold 

def _fold_status(self, dt_utc, dt_wall):
        """
        Determine the fold status of a "wall" datetime, given a representation
        of the same datetime as a (naive) UTC datetime. This is calculated based
        on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
        datetimes, and that this offset is the actual number of hours separating
        ``dt_utc`` and ``dt_wall``.

        :param dt_utc:
            Representation of the datetime as UTC

        :param dt_wall:
            Representation of the datetime as "wall time". This parameter must
            either have a `fold` attribute or have a fold-naive
            :class:`datetime.tzinfo` attached, otherwise the calculation may
            fail.
        """
        if self.is_ambiguous(dt_wall):
            delta_wall = dt_wall - dt_utc
            _fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
        else:
            _fold = 0

        return _fold 

def is_ambiguous(self, dt):
        """
        Whether or not the "wall time" of a given datetime is ambiguous in this
        zone.

        :param dt:
            A :py:class:`datetime.datetime`, naive or time zone aware.


        :return:
            Returns ``True`` if ambiguous, ``False`` otherwise.

        .. versionadded:: 2.6.0
        """
        if not self.hasdst:
            return False

        start, end = self.transitions(dt.year)

        dt = dt.replace(tzinfo=None)
        return (end <= dt < end + self._dst_base_offset) 

def _isdst(self, dt):
        if not self.hasdst:
            return False
        elif dt is None:
            return None

        transitions = self.transitions(dt.year)

        if transitions is None:
            return False

        dt = dt.replace(tzinfo=None)

        isdst = self._naive_isdst(dt, transitions)

        # Handle ambiguous dates
        if not isdst and self.is_ambiguous(dt):
            return not self._fold(dt)
        else:
            return isdst 

def is_ambiguous(self, dt):
        """
        Whether or not the "wall time" of a given datetime is ambiguous in this
        zone.

        :param dt:
            A :py:class:`datetime.datetime`, naive or time zone aware.


        :return:
            Returns ``True`` if ambiguous, ``False`` otherwise.

        .. versionadded:: 2.6.0
        """
        if not self.hasdst:
            return False

        start, end = self.transitions(dt.year)

        dt = dt.replace(tzinfo=None)
        return (end <= dt < end + self._dst_base_offset) 

def __sub__(self, other):
        if PY38:
            result = datetime(
                self.year,
                self.month,
                self.day,
                self.hour,
                self.minute,
                self.second,
                self.microsecond,
                self.tzinfo,
            ).__sub__(other)
        else:
            result = super(DateTime, self).__sub__(other)

        if isinstance(result, datetime):
            result = self._new(result)

        return result 

def __add__(self, other):
        if PY38:
            result = datetime(
                self.year,
                self.month,
                self.day,
                self.hour,
                self.minute,
                self.second,
                self.microsecond,
                self.tzinfo,
            ).__add__(other)
        else:
            result = super(DateTime, self).__add__(other)

        return self._new(result) 

def is_ambiguous(self, dt):
        """
        Whether or not the "wall time" of a given datetime is ambiguous in this
        zone.

        :param dt:
            A :py:class:`datetime.datetime`, naive or time zone aware.


        :return:
            Returns ``True`` if ambiguous, ``False`` otherwise.

        .. versionadded:: 2.6.0
        """

        dt = dt.replace(tzinfo=self)

        wall_0 = enfold(dt, fold=0)
        wall_1 = enfold(dt, fold=1)

        same_offset = wall_0.utcoffset() == wall_1.utcoffset()
        same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)

        return same_dt and not same_offset 

def is_ambiguous(self, dt):
        """
        Whether or not the "wall time" of a given datetime is ambiguous in this
        zone.

        :param dt:
            A :py:class:`datetime.datetime`, naive or time zone aware.


        :return:
            Returns ``True`` if ambiguous, ``False`` otherwise.

        .. versionadded:: 2.6.0
        """
        if not self.hasdst:
            return False

        start, end = self.transitions(dt.year)

        dt = dt.replace(tzinfo=None)
        return (end <= dt < end + self._dst_base_offset) 

def is_ambiguous(self, dt):
        """
        Whether or not the "wall time" of a given datetime is ambiguous in this
        zone.

        :param dt:
            A :py:class:`datetime.datetime`, naive or time zone aware.


        :return:
            Returns ``True`` if ambiguous, ``False`` otherwise.

        .. versionadded:: 2.6.0
        """

        dt = dt.replace(tzinfo=self)

        wall_0 = enfold(dt, fold=0)
        wall_1 = enfold(dt, fold=1)

        same_offset = wall_0.utcoffset() == wall_1.utcoffset()
        same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)

        return same_dt and not same_offset 

def _isdst(self, dt):
        if not self.hasdst:
            return False
        elif dt is None:
            return None

        transitions = self.transitions(dt.year)

        if transitions is None:
            return False

        dt = dt.replace(tzinfo=None)

        isdst = self._naive_isdst(dt, transitions)

        # Handle ambiguous dates
        if not isdst and self.is_ambiguous(dt):
            return not self._fold(dt)
        else:
            return isdst 

def is_ambiguous(self, dt):
        """
        Whether or not the "wall time" of a given datetime is ambiguous in this
        zone.

        :param dt:
            A :py:class:`datetime.datetime`, naive or time zone aware.


        :return:
            Returns ``True`` if ambiguous, ``False`` otherwise.

        .. versionadded:: 2.6.0
        """
        if not self.hasdst:
            return False

        start, end = self.transitions(dt.year)

        dt = dt.replace(tzinfo=None)
        return (end <= dt < end + self._dst_base_offset) 

def _fold_status(self, dt_utc, dt_wall):
        """
        Determine the fold status of a "wall" datetime, given a representation
        of the same datetime as a (naive) UTC datetime. This is calculated based
        on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
        datetimes, and that this offset is the actual number of hours separating
        ``dt_utc`` and ``dt_wall``.

        :param dt_utc:
            Representation of the datetime as UTC

        :param dt_wall:
            Representation of the datetime as "wall time". This parameter must
            either have a `fold` attribute or have a fold-naive
            :class:`datetime.tzinfo` attached, otherwise the calculation may
            fail.
        """
        if self.is_ambiguous(dt_wall):
            delta_wall = dt_wall - dt_utc
            _fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
        else:
            _fold = 0

        return _fold 

def is_ambiguous(self, dt):
        """
        Whether or not the "wall time" of a given datetime is ambiguous in this
        zone.

        :param dt:
            A :py:class:`datetime.datetime`, naive or time zone aware.


        :return:
            Returns ``True`` if ambiguous, ``False`` otherwise.

        ..versionadded:: 2.6.0
        """

        dt = dt.replace(tzinfo=self)

        wall_0 = enfold(dt, fold=0)
        wall_1 = enfold(dt, fold=1)

        same_offset = wall_0.utcoffset() == wall_1.utcoffset()
        same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)
        
        return same_dt and not same_offset 

def is_ambiguous(self, dt):
        """
        Whether or not the "wall time" of a given datetime is ambiguous in this
        zone.

        :param dt:
            A :py:class:`datetime.datetime`, naive or time zone aware.


        :return:
            Returns ``True`` if ambiguous, ``False`` otherwise.

        ..versionadded:: 2.6.0
        """

        dt = dt.replace(tzinfo=self)

        wall_0 = enfold(dt, fold=0)
        wall_1 = enfold(dt, fold=1)

        same_offset = wall_0.utcoffset() == wall_1.utcoffset()
        same_dt = wall_0.replace(tzinfo=None) == wall_1.replace(tzinfo=None)
        
        return same_dt and not same_offset 

def tz_to_dtype(tz):
    """
    Return a datetime64[ns] dtype appropriate for the given timezone.

    Parameters
    ----------
    tz : tzinfo or None

    Returns
    -------
    np.dtype or Datetime64TZDType
    """
    if tz is None:
        return _NS_DTYPE
    else:
        return DatetimeTZDtype(tz=tz) 

def _fold_status(self, dt_utc, dt_wall):
        """
        Determine the fold status of a "wall" datetime, given a representation
        of the same datetime as a (naive) UTC datetime. This is calculated based
        on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
        datetimes, and that this offset is the actual number of hours separating
        ``dt_utc`` and ``dt_wall``.

        :param dt_utc:
            Representation of the datetime as UTC

        :param dt_wall:
            Representation of the datetime as "wall time". This parameter must
            either have a `fold` attribute or have a fold-naive
            :class:`datetime.tzinfo` attached, otherwise the calculation may
            fail.
        """
        if self.is_ambiguous(dt_wall):
            delta_wall = dt_wall - dt_utc
            _fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
        else:
            _fold = 0

        return _fold 

def _fold_status(self, dt_utc, dt_wall):
        """
        Determine the fold status of a "wall" datetime, given a representation
        of the same datetime as a (naive) UTC datetime. This is calculated based
        on the assumption that ``dt.utcoffset() - dt.dst()`` is constant for all
        datetimes, and that this offset is the actual number of hours separating
        ``dt_utc`` and ``dt_wall``.

        :param dt_utc:
            Representation of the datetime as UTC

        :param dt_wall:
            Representation of the datetime as "wall time". This parameter must
            either have a `fold` attribute or have a fold-naive
            :class:`datetime.tzinfo` attached, otherwise the calculation may
            fail.
        """
        if self.is_ambiguous(dt_wall):
            delta_wall = dt_wall - dt_utc
            _fold = int(delta_wall == (dt_utc.utcoffset() - dt_utc.dst()))
        else:
            _fold = 0

        return _fold 

def _isdst(self, dt):
        if not self.hasdst:
            return False
        elif dt is None:
            return None

        transitions = self.transitions(dt.year)

        if transitions is None:
            return False

        dt = dt.replace(tzinfo=None)

        isdst = self._naive_isdst(dt, transitions)

        # Handle ambiguous dates
        if not isdst and self.is_ambiguous(dt):
            return not self._fold(dt)
        else:
            return isdst 

def _isdst(self, dt):
        if not self.hasdst:
            return False
        elif dt is None:
            return None

        transitions = self.transitions(dt.year)

        if transitions is None:
            return False

        dt = dt.replace(tzinfo=None)

        isdst = self._naive_isdst(dt, transitions)

        # Handle ambiguous dates
        if not isdst and self.is_ambiguous(dt):
            return not self._fold(dt)
        else:
            return isdst 

def today(tzinfo=None):
    """
    Returns a :py:class:`datetime` representing the current day at midnight

    :param tzinfo:
        The time zone to attach (also used to determine the current day).

    :return:
        A :py:class:`datetime.datetime` object representing the current day
        at midnight.
    """

    dt = datetime.now(tzinfo)
    return datetime.combine(dt.date(), time(0, tzinfo=tzinfo)) 

def _datetime_to_timestamp(dt):
    """
    Convert a :class:`datetime.datetime` object to an epoch timestamp in
    seconds since January 1, 1970, ignoring the time zone.
    """
    return (dt.replace(tzinfo=None) - EPOCH).total_seconds() 

def __init__(self):
        """Initializer."""
        if Config.MASU_DATE_OVERRIDE and Config.DEBUG and DateAccessor.mock_date_time is None:
            # python-dateutil is needed in Python <=3.6.x;
            # in Python 3.7 there is datetime.fromisoformat()
            DateAccessor.mock_date_time = parser.parse(Config.MASU_DATE_OVERRIDE)
            if DateAccessor.mock_date_time.tzinfo is None:
                DateAccessor.mock_date_time = DateAccessor.mock_date_time.replace(tzinfo=pytz.UTC)
            LOG.info("Initializing masu date/time to %s", str(DateAccessor.mock_date_time)) 

def enfold(dt, fold=1):
        """
        Provides a unified interface for assigning the ``fold`` attribute to
        datetimes both before and after the implementation of PEP-495.

        :param fold:
            The value for the ``fold`` attribute in the returned datetime. This
            should be either 0 or 1.

        :return:
            Returns an object for which ``getattr(dt, 'fold', 0)`` returns
            ``fold`` for all versions of Python. In versions prior to
            Python 3.6, this is a ``_DatetimeWithFold`` object, which is a
            subclass of :py:class:`datetime.datetime` with the ``fold``
            attribute added, if ``fold`` is 1.

        ..versionadded:: 2.6.0
        """
        if getattr(dt, 'fold', 0) == fold:
            return dt

        args = dt.timetuple()[:6]
        args += (dt.microsecond, dt.tzinfo)

        if fold:
            return _DatetimeWithFold(*args)
        else:
            return datetime(*args) 

def datetime_exists(dt, tz=None):
    """
    Given a datetime and a time zone, determine whether or not a given datetime
    would fall in a gap.

    :param dt:
        A :class:`datetime.datetime` (whose time zone will be ignored if ``tz``
        is provided.)

    :param tz:
        A :class:`datetime.tzinfo` with support for the ``fold`` attribute. If
        ``None`` or not provided, the datetime's own time zone will be used.

    :return:
        Returns a boolean value whether or not the "wall time" exists in
        ``tz``.

    .. versionadded:: 2.7.0
    """
    if tz is None:
        if dt.tzinfo is None:
            raise ValueError('Datetime is naive and no time zone provided.')
        tz = dt.tzinfo

    dt = dt.replace(tzinfo=None)

    # This is essentially a test of whether or not the datetime can survive
    # a round trip to UTC.
    dt_rt = dt.replace(tzinfo=tz).astimezone(tzutc()).astimezone(tz)
    dt_rt = dt_rt.replace(tzinfo=None)

    return dt == dt_rt 

def fromutc(self, dt):
        """ Given a datetime in UTC, return local time """
        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")

        # Get transitions - if there are none, fixed offset
        transitions = self.transitions(dt.year)
        if transitions is None:
            return dt + self.utcoffset(dt)

        # Get the transition times in UTC
        dston, dstoff = transitions

        dston -= self._std_offset
        dstoff -= self._std_offset

        utc_transitions = (dston, dstoff)
        dt_utc = dt.replace(tzinfo=None)


        isdst = self._naive_isdst(dt_utc, utc_transitions)

        if isdst:
            dt_wall = dt + self._dst_offset
        else:
            dt_wall = dt + self._std_offset

        _fold = int(not isdst and self.is_ambiguous(dt_wall))

        return enfold(dt_wall, fold=_fold) 

def today_with_timezone(self, timezone):
        """Return the current datetime at the timezone indictated.

        When the environment variable MASU_DEBUG is set to True,
        the MASU_DATE_OVERRIDE environment variable can be used to
        override masu's current date and time.

        Args:
            timezone (str/datetime.tzinfo) Either a valid timezone string
                or an instance or subclass of datetime.tzinfo.
            examples: 'US/Eastern', pytz.UTC


        Returns:
            (datetime.datetime): Current datetime object
            example: 2018-07-24 15:47:33

        """
        if isinstance(timezone, str):
            try:
                timezone = pytz.timezone(timezone)
            except pytz.exceptions.UnknownTimeZoneError as err:
                LOG.error(err)
                raise DateAccessorError(err)
        elif not isinstance(timezone, tzinfo):
            err = "timezone must be a valid timezone string or subclass of datetime.tzinfo"
            raise DateAccessorError(err)

        current_date = datetime.now(tz=timezone)
        if Config.DEBUG and DateAccessor.mock_date_time:
            seconds_delta = current_date - DateAccessor.date_time_last_accessed
            DateAccessor.date_time_last_accessed = current_date

            DateAccessor.mock_date_time = DateAccessor.mock_date_time + seconds_delta
            current_date = DateAccessor.mock_date_time

        return current_date 

def _delta(self, x, isend=0):
        from dateutil import relativedelta
        kwargs = {}
        if x.month is not None:
            kwargs["month"] = x.month
            if x.weekday is not None:
                kwargs["weekday"] = relativedelta.weekday(x.weekday, x.week)
                if x.week > 0:
                    kwargs["day"] = 1
                else:
                    kwargs["day"] = 31
            elif x.day:
                kwargs["day"] = x.day
        elif x.yday is not None:
            kwargs["yearday"] = x.yday
        elif x.jyday is not None:
            kwargs["nlyearday"] = x.jyday
        if not kwargs:
            # Default is to start on first sunday of april, and end
            # on last sunday of october.
            if not isend:
                kwargs["month"] = 4
                kwargs["day"] = 1
                kwargs["weekday"] = relativedelta.SU(+1)
            else:
                kwargs["month"] = 10
                kwargs["day"] = 31
                kwargs["weekday"] = relativedelta.SU(-1)
        if x.time is not None:
            kwargs["seconds"] = x.time
        else:
            # Default is 2AM.
            kwargs["seconds"] = 7200
        if isend:
            # Convert to standard time, to follow the documented way
            # of working with the extra hour. See the documentation
            # of the tzinfo class.
            delta = self._dst_offset - self._std_offset
            kwargs["seconds"] -= delta.seconds + delta.days * 86400
        return relativedelta.relativedelta(**kwargs)