`riptable.rt_timezone`

Classes

TimeZone

Stores daylight savings cutoff information so UTC times can be translated to zone-specific times.

class riptable.rt_timezone.TimeZone(from_tz=None, to_tz='NYC')

Stores daylight savings cutoff information so UTC times can be translated to zone-specific times. Every DateTimeNano object holds a TimeZone object. All timezone-related conversions / fixups will be handled by the TimeZone class.

Parameters:

from_tz (str, defaults to None) –
to_tz (str) –

_from_tz

tz databse timezone name - the timezone that the time originates from

Type:: str

_dst_cutoffs

lookup array for converting times from constructor to UTC nano in GMT time

Type:: numpy.ndarray

_to_tz

tz database timezone name - the timezone that the time will be displayed in

Type:: str

_timezone_str: same as _to_str. NOTE: This is actually a property, not a regular attribute.

_dst_reverse

lookup array for DateTimeNano to display time in the correct timezone, accounting for daylight savings.

Type:: numpy.ndarray

_offset: offset from GMT for display (non daylight savings)

_fix_offset: the offset from the timezone of origin

Notes

‘UTC’ is not a timezone, but accepted as an alias for GMT

property _timezone_str: Get _to_tz, which is the name for this timezone within the ‘tz’ database.

_ALIAS_TIMEZONE_NAMES

_TZDB_TIMEZONE_NAMES = ['America/New_York', 'Europe/Dublin', 'UTC', 'GMT', 'Australia/Sydney', 'Asia/Hong_Kong',...

tz_error_msg

valid_timezones

__eq__(other): Return self==value.

__repr__(): Return repr(self).

classmethod _init_from_tz(from_tz)

classmethod _init_to_tz(to_tz): Return daylight savings information, timezone string for correctly displaying the datetime based on the to_tz keyword in the constructor.

_is_dst(arr)

_mask_dst(arr, cutoffs=None)

Parameters:

arr – int64 UTC nanoseconds
cutoffs – an array containing daylight savings time starts/ends at midnight possibly a reverse array for GMT that compensates for New York timezone (see DST_REVERSE_NYC)

_set_timezone(tz): See DateTimeNano.set_timezone()

_tz_offset(arr)

copy(): A shallow copy of the TimeZone - all attributes are scalars or references to constants.

fix_dst(arr, cutoffs=None)

Called by DateTimeNano routines that need to adjust time for timezone. Also called by DateTimeNanoScalar

Parameters:

arr (underlying array of int64, UTC nanoseconds OR a scalar np.int64) –
cutoffs (lookup array for daylight savings time cutoffs for the active timezone) –

Notes

There is a difference in daylight savings fixup for Dublin timezone. The python datetime.astimezone() routine works differently than fromutctimestamp(). Python datetime may set a ‘fold’ attribute, indicating that the time is invalid, within an ambiguous daylight savings hour.

>>> import datetime
>>> from dateutil import tz

>>> zone = tz.gettz('Europe/Dublin')
>>> pdt0 = datetime.datetime(2018, 10, 28, 1, 59, 0, tzinfo=zone)
>>> pdt1 = datetime.datetime(2018, 10, 28, 2, 59, 0, tzinfo=zone)
>>> dtn = DateTimeNano(['2018-10-28 01:59', '2018-10-28 02:59'], from_tz='DUBLIN', to_tz='DUBLIN')
>>> utc = datetime.timezone.utc

>>> pdt0.astimezone(utc)
datetime.datetime(2018, 10, 28, 0, 59, tzinfo=datetime.timezone.utc)

>>> pdt1.astimezone(utc)
datetime.datetime(2018, 10, 28, 1, 59, tzinfo=datetime.timezone.utc)

>>> dtn.astimezone('GMT')
DateTimeNano([20181028 00:59:00.000000000, 20181028 02:59:00.000000000])

static normalize_tz_to_tzdb_name(tz_name)

to_utc(dtn, inv_mask=None): Called in the DateTimeNano constructor. If necessary, integer arrays of nanoseconds are converted from their timezone of origin to UTC nanoseconds in GMT. Restores any invalids (0) from the original array. This differs from fix_dst() because it adds the offset to the array.

riptable.rt_timezone

Classes

`riptable.rt_timezone`