Python datetime.datetime.datetime() Examples

def __init__(
        self,
        client_type,
        region_name=None,
        profile_name=None,
        start_time=None,
        end_time=None,
        boto_client_kwargs=None,
        boto_client=None,
    ):
        # Get a boto3 client with which to perform queries
        if boto_client is not None:
            self.boto_client = boto_client
        else:
            self.boto_client = self._get_client(
                client_type, region_name, profile_name, boto_client_kwargs
            )

        # If no time filters are given use the last hour
        now = datetime.utcnow()
        self.start_time = start_time or now - timedelta(hours=1)
        self.end_time = end_time or now

        # Initialize the iterator
        self.iterator = self._reader() 

def generalized_time_from_datetime(date):
    """Convert given ``datetime.datetime`` object `date` to an ASN.1
    generalized time string.

    """

    if date.second == 0:
        if date.microsecond > 0:
            string = date.strftime('%Y%m%d%H%M.%f').rstrip('0')
        else:
            string = date.strftime('%Y%m%d%H%M')
    else:
        if date.microsecond > 0:
            string = date.strftime('%Y%m%d%H%M%S.%f').rstrip('0')
        else:
            string = date.strftime('%Y%m%d%H%M%S')

    if date.tzinfo is not None:
        if date.utcoffset():
            string += date.strftime('%z')
        else:
            string += 'Z'

    return string 

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
        """
        naive_dst = self._naive_is_dst(dt)
        return (not naive_dst and
                (naive_dst != self._naive_is_dst(dt - self._dst_saved))) 

def datereader(dateattribute, parsingfunction=ymdparser):
    """Return a function that converts a certain dict member to a datetime.date

       When setting, fromfinder for a tables.SlowlyChangingDimension, this
       method can be used for generating a function that picks the relevant
       dictionary member from each row and converts it.

       Arguments:
           
       - dateattribute: the attribute the generated function should read
       - parsingfunction: the parsing function that converts the string
         to a datetime.date
    """
    def readerfunction(targetconnection, row, namemapping={}):
        atttouse = (namemapping.get(dateattribute) or dateattribute)
        return parsingfunction(row[atttouse])  # a datetime.date

    return readerfunction 

def _get_keys(self, prefix):
        # S3 keys have a file name like:
        # account_vpcflowlogs_region_flow-logs-id_datetime_hash.log.gz
        # Yield the keys for files relevant to our time range
        paginator = self.boto_client.get_paginator('list_objects_v2')
        all_pages = paginator.paginate(Bucket=self.bucket, Prefix=prefix)
        for page in all_pages:
            for item in page.get('Contents', []):
                key = item['Key']
                file_name = basename(key)
                try:
                    dt = datetime.strptime(
                        file_name.rsplit('_', 2)[1], '%Y%m%dT%H%MZ'
                    )
                except (IndexError, ValueError):
                    continue

                if self.start_time <= dt < self.end_time:
                    yield key 

def restricted_utc_time_to_datetime(string):
    """Convert given restricted ASN.1 UTC time string `string` to a
    ``datetime.datetime`` object.

    """

    try:
        if string[-1] != 'Z':
            raise ValueError

        if len(string) != 13:
            raise ValueError

        return datetime.strptime(string[:-1], '%y%m%d%H%M%S')
    except (ValueError, IndexError):
        raise Error(
            "Expected a restricted UTC time string, but got '{}'.".format(
                string)) 

def utc_time_from_datetime(date):
    """Convert given ``datetime.datetime`` object `date` to an ASN.1 UTC
    time string.

    """

    fmt = '%y%m%d%H%M'

    if date.second > 0:
        fmt += '%S'

    if date.tzinfo is None:
        fmt += 'Z'
    else:
        fmt += '%z'

    return date.strftime(fmt) 

def utc_time_to_datetime(string):
    """Convert given ASN.1 UTC time string `string` to a
    ``datetime.datetime`` object.

    """

    length = len(string)

    try:
        if string[-1] == 'Z':
            if length == 11:
                return datetime.strptime(string[:-1], '%y%m%d%H%M')
            elif length == 13:
                return datetime.strptime(string[:-1], '%y%m%d%H%M%S')
            else:
                raise ValueError
        elif length == 15:
            return compat.strptime(string, '%y%m%d%H%M%z')
        elif length == 17:
            return compat.strptime(string, '%y%m%d%H%M%S%z')
        else:
            raise ValueError
    except (ValueError, IndexError):
        raise Error(
            "Expected a UTC time string, but got '{}'.".format(string)) 

def _generalized_time_to_datetime(string):
    length = len(string)

    if '.' in string:
        try:
            return datetime.strptime(string, '%Y%m%d%H%M.%f')
        except ValueError:
            return datetime.strptime(string, '%Y%m%d%H%M%S.%f')
    elif ',' in string:
        try:
            return datetime.strptime(string, '%Y%m%d%H%M,%f')
        except ValueError:
            return datetime.strptime(string, '%Y%m%d%H%M%S,%f')
    elif length == 12:
        return datetime.strptime(string, '%Y%m%d%H%M')
    elif length == 14:
        return datetime.strptime(string, '%Y%m%d%H%M%S')
    else:
        raise ValueError 

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
        """
        return dt.replace(fold=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 dump_age(age=None):
    """Formats the duration as a base-10 integer.

    :param age: should be an integer number of seconds,
                a :class:`datetime.timedelta` object, or,
                if the age is unknown, `None` (default).
    """
    if age is None:
        return
    if isinstance(age, timedelta):
        # do the equivalent of Python 2.7's timedelta.total_seconds(),
        # but disregarding fractional seconds
        age = age.seconds + (age.days * 24 * 3600)

    age = int(age)
    if age < 0:
        raise ValueError("age cannot be negative")

    return str(age) 

def check_date_limit(self, data, verbose=False):
        """
        Validate date limits.
        """
        if self.upper_date_limit or self.lower_date_limit:
            date_fmt = '%a %b %d %H:%M:%S +0000 %Y'
            tweet_date = \
                datetime.strptime(data['created_at'],
                                  date_fmt).replace(tzinfo=UTC)
            if (self.upper_date_limit and tweet_date > self.upper_date_limit) or \
               (self.lower_date_limit and tweet_date < self.lower_date_limit):
                if self.upper_date_limit:
                    message = "earlier"
                    date_limit = self.upper_date_limit
                else:
                    message = "later"
                    date_limit = self.lower_date_limit
                if verbose:
                    print("Date limit {0} is {1} than date of current tweet {2}".\
                      format(date_limit, message, tweet_date))
                self.do_stop = True 

def fromutc(self, dt):
        """
        Given a timezone-aware datetime in a given timezone, calculates a
        timezone-aware datetime in a new timezone.

        Since this is the one time that we *know* we have an unambiguous
        datetime object, we take this opportunity to determine whether the
        datetime is ambiguous and in a "fold" state (e.g. if it's the first
        occurance, chronologically, of the ambiguous datetime).

        :param dt:
            A timezone-aware :class:`datetime.datetime` object.
        """
        dt_wall = self._fromutc(dt)

        # Calculate the fold status given the two datetimes.
        _fold = self._fold_status(dt, dt_wall)

        # Set the default fold value for ambiguous dates
        return enfold(dt_wall, fold=_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 get_datetime(self, timestamp: str, unix=True):
        """Converts a %Y%m%dT%H%M%S.%fZ to a UNIX timestamp
        or a datetime.datetime object

        Parameters
        ---------
        timestamp: str
            A timstamp in the %Y%m%dT%H%M%S.%fZ format, usually returned by the API
            in the ``created_time`` field for example (eg. 20180718T145906.000Z)
        unix: Optional[bool] = True
            Whether to return a POSIX timestamp (seconds since epoch) or not

        Returns int or datetime.datetime
        """
        time = datetime.strptime(timestamp, '%Y%m%dT%H%M%S.%fZ')
        if unix:
            return int(time.timestamp())
        else:
            return time 

def http_date(timestamp=None):
    """Formats the time to match the RFC1123 date format.

    Accepts a floating point number expressed in seconds since the epoch in, a
    datetime object or a timetuple.  All times in UTC.  The :func:`parse_date`
    function can be used to parse such a date.

    Outputs a string in the format ``Wdy, DD Mon YYYY HH:MM:SS GMT``.

    :param timestamp: If provided that date is used, otherwise the current.
    """
    return _dump_date(timestamp, " ") 

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
        """
        return False 

def cookie_date(expires=None):
    """Formats the time to ensure compatibility with Netscape's cookie
    standard.

    Accepts a floating point number expressed in seconds since the epoch in, a
    datetime object or a timetuple.  All times in UTC.  The :func:`parse_date`
    function can be used to parse such a date.

    Outputs a string in the format ``Wdy, DD-Mon-YYYY HH:MM:SS GMT``.

    :param expires: If provided that date is used, otherwise the current.
    """
    return _dump_date(expires, "-") 

def _dump_date(d, delim):
    """Used for `http_date` and `cookie_date`."""
    if d is None:
        d = gmtime()
    elif isinstance(d, datetime):
        d = d.utctimetuple()
    elif isinstance(d, (integer_types, float)):
        d = gmtime(d)
    return "%s, %02d%s%s%s%s %02d:%02d:%02d GMT" % (
        ("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun")[d.tm_wday],
        d.tm_mday,
        delim,
        (
            "Jan",
            "Feb",
            "Mar",
            "Apr",
            "May",
            "Jun",
            "Jul",
            "Aug",
            "Sep",
            "Oct",
            "Nov",
            "Dec",
        )[d.tm_mon - 1],
        delim,
        str(d.tm_year),
        d.tm_hour,
        d.tm_min,
        d.tm_sec,
    ) 

def get(self, tzid=None):
        """
        Retrieve a :py:class:`datetime.tzinfo` object by its ``tzid``.

        :param tzid:
            If there is exactly one time zone available, omitting ``tzid``
            or passing :py:const:`None` value returns it. Otherwise a valid
            key (which can be retrieved from :func:`keys`) is required.

        :raises ValueError:
            Raised if ``tzid`` is not specified but there are either more
            or fewer than 1 zone defined.

        :returns:
            Returns either a :py:class:`datetime.tzinfo` object representing
            the relevant time zone or :py:const:`None` if the ``tzid`` was
            not found.
        """
        if tzid is None:
            if len(self._vtz) == 0:
                raise ValueError("no timezones defined")
            elif len(self._vtz) > 1:
                raise ValueError("more than one timezone available")
            tzid = next(iter(self._vtz))

        return self._vtz.get(tzid) 

def __init__(self, tzoffsetfrom, tzoffsetto, isdst,
                 tzname=None, rrule=None):
        self.tzoffsetfrom = datetime.timedelta(seconds=tzoffsetfrom)
        self.tzoffsetto = datetime.timedelta(seconds=tzoffsetto)
        self.tzoffsetdiff = self.tzoffsetto - self.tzoffsetfrom
        self.isdst = isdst
        self.tzname = tzname
        self.rrule = rrule 

def is_ambiguous(self, dt, idx=None):
        """
        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 idx is None:
            idx = self._find_last_transition(dt)

        # Calculate the difference in offsets from current to previous
        timestamp = _datetime_to_timestamp(dt)
        tti = self._get_ttinfo(idx)

        if idx is None or idx <= 0:
            return False

        od = self._get_ttinfo(idx - 1).offset - tti.offset
        tt = self._trans_list[idx]          # Transition time

        return timestamp < tt + od 

def fromutc(self, dt):
        """
        The ``tzfile`` implementation of :py:func:`datetime.tzinfo.fromutc`.

        :param dt:
            A :py:class:`datetime.datetime` object.

        :raises TypeError:
            Raised if ``dt`` is not a :py:class:`datetime.datetime` object.

        :raises ValueError:
            Raised if this is called with a ``dt`` which does not have this
            ``tzinfo`` attached.

        :return:
            Returns a :py:class:`datetime.datetime` object representing the
            wall time in ``self``'s time zone.
        """
        # These isinstance checks are in datetime.tzinfo, so we'll preserve
        # them, even if we don't care about duck typing.
        if not isinstance(dt, datetime.datetime):
            raise TypeError("fromutc() requires a datetime argument")

        if dt.tzinfo is not self:
            raise ValueError("dt.tzinfo is not self")

        # First treat UTC as wall time and get the transition we're in.
        idx = self._find_last_transition(dt, in_utc=True)
        tti = self._get_ttinfo(idx)

        dt_out = dt + datetime.timedelta(seconds=tti.offset)

        fold = self.is_ambiguous(dt_out, idx=idx)

        return enfold(dt_out, fold=int(fold)) 

def _isdst(self, dt, fold_naive=True):
        # We can't use mktime here. It is unstable when deciding if
        # the hour near to a change is DST or not.
        #
        # timestamp = time.mktime((dt.year, dt.month, dt.day, dt.hour,
        #                         dt.minute, dt.second, dt.weekday(), 0, -1))
        # return time.localtime(timestamp).tm_isdst
        #
        # The code above yields the following result:
        #
        # >>> import tz, datetime
        # >>> t = tz.tzlocal()
        # >>> datetime.datetime(2003,2,15,23,tzinfo=t).tzname()
        # 'BRDT'
        # >>> datetime.datetime(2003,2,16,0,tzinfo=t).tzname()
        # 'BRST'
        # >>> datetime.datetime(2003,2,15,23,tzinfo=t).tzname()
        # 'BRST'
        # >>> datetime.datetime(2003,2,15,22,tzinfo=t).tzname()
        # 'BRDT'
        # >>> datetime.datetime(2003,2,15,23,tzinfo=t).tzname()
        # 'BRDT'
        #
        # Here is a more stable implementation:
        #
        if not self._hasdst:
            return False

        # Check for ambiguous times:
        dstval = self._naive_is_dst(dt)
        fold = getattr(dt, 'fold', None)

        if self.is_ambiguous(dt):
            if fold is not None:
                return not self._fold(dt)
            else:
                return True

        return dstval 

def ymdparser(ymdstr):
    """Convert a string of the form 'yyyy-MM-dd' to a datetime.date.

       If the input is None, the return value is also None.
    """
    if ymdstr is None:
        return None
    (year, month, day) = ymdstr.split('-')
    return date(int(year), int(month), int(day)) 

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
        """
        return False 

def __init__(self, name, offset):
        self._name = name

        try:
            # Allow a timedelta
            offset = offset.total_seconds()
        except (TypeError, AttributeError):
            pass
        self._offset = datetime.timedelta(seconds=offset) 

def fromutc(self, dt):
        """
        Fast track version of fromutc() returns the original ``dt`` object for
        any valid :py:class:`datetime.datetime` object.
        """
        return dt