tz

class dateutil.tz.tzutc[source]

This is a tzinfo object that represents the UTC time zone.

Examples:

>>> from datetime import *
>>> from dateutil.tz import *

>>> datetime.now()
datetime.datetime(2003, 9, 27, 9, 40, 1, 521290)

>>> datetime.now(tzutc())
datetime.datetime(2003, 9, 27, 12, 40, 12, 156379, tzinfo=tzutc())

>>> datetime.now(tzutc()).tzname()
'UTC'

Changed in version 2.7.0: tzutc() is now a singleton, so the result of tzutc() will always return the same object.

>>> from dateutil.tz import tzutc, UTC
>>> tzutc() is tzutc()
True
>>> tzutc() is UTC
True
dst(dt)[source]
fromutc(dt)[source]

Fast track version of fromutc() returns the original dt object for any valid datetime.datetime object.

is_ambiguous(dt)[source]

Whether or not the “wall time” of a given datetime is ambiguous in this zone.

Parameters:dt – A datetime.datetime, naive or time zone aware.
Returns:Returns True if ambiguous, False otherwise.

New in version 2.6.0.

tzname(*args, **kwargs)
utcoffset(dt)[source]
class dateutil.tz.tzoffset(name, offset)[source]

A simple class for representing a fixed offset from UTC.

Parameters:
  • name – The timezone name, to be returned when tzname() is called.
  • offset – The time zone offset in seconds, or (since version 2.6.0, represented as a datetime.timedelta object).
dst(dt)[source]
fromutc(dt)[source]
is_ambiguous(dt)[source]

Whether or not the “wall time” of a given datetime is ambiguous in this zone.

Parameters:dt – A datetime.datetime, naive or time zone aware.
Returns:Returns True if ambiguous, False otherwise.

New in version 2.6.0.

tzname(*args, **kwargs)
utcoffset(dt)[source]
class dateutil.tz.tzlocal[source]

A tzinfo subclass built around the time timezone functions.

dst(dt)[source]
is_ambiguous(dt)[source]

Whether or not the “wall time” of a given datetime is ambiguous in this zone.

Parameters:dt – A datetime.datetime, naive or time zone aware.
Returns:Returns True if ambiguous, False otherwise.

New in version 2.6.0.

tzname(*args, **kwargs)
utcoffset(dt)[source]
class dateutil.tz.tzfile(fileobj, filename=None)[source]

This is a tzinfo subclass thant allows one to use the tzfile(5) format timezone files to extract current and historical zone information.

Parameters:
  • fileobj – This can be an opened file stream or a file name that the time zone information can be read from.
  • filename – This is an optional parameter specifying the source of the time zone information in the event that fileobj is a file object. If omitted and fileobj is a file stream, this parameter will be set either to fileobj’s name attribute or to repr(fileobj).

See Sources for Time Zone and Daylight Saving Time Data for more information. Time zone files can be compiled from the IANA Time Zone database files with the zic time zone compiler

dst(dt)[source]
fromutc(dt)[source]

The tzfile implementation of datetime.tzinfo.fromutc().

Parameters:

dt – A datetime.datetime object.

Raises:
  • TypeError – Raised if dt is not a datetime.datetime object.
  • ValueError – Raised if this is called with a dt which does not have this tzinfo attached.
Returns:

Returns a datetime.datetime object representing the wall time in self’s time zone.

is_ambiguous(dt, idx=None)[source]

Whether or not the “wall time” of a given datetime is ambiguous in this zone.

Parameters:dt – A datetime.datetime, naive or time zone aware.
Returns:Returns True if ambiguous, False otherwise.

New in version 2.6.0.

tzname(*args, **kwargs)
utcoffset(dt)[source]
class dateutil.tz.tzrange(stdabbr, stdoffset=None, dstabbr=None, dstoffset=None, start=None, end=None)[source]

The tzrange object is a time zone specified by a set of offsets and abbreviations, equivalent to the way the TZ variable can be specified in POSIX-like systems, but using Python delta objects to specify DST start, end and offsets.

Parameters:
  • stdabbr – The abbreviation for standard time (e.g. 'EST').
  • stdoffset

    An integer or datetime.timedelta object or equivalent specifying the base offset from UTC.

    If unspecified, +00:00 is used.

  • dstabbr

    The abbreviation for DST / “Summer” time (e.g. 'EDT').

    If specified, with no other DST information, DST is assumed to occur and the default behavior or dstoffset, start and end is used. If unspecified and no other DST information is specified, it is assumed that this zone has no DST.

    If this is unspecified and other DST information is is specified, DST occurs in the zone but the time zone abbreviation is left unchanged.

  • dstoffset – A an integer or datetime.timedelta object or equivalent specifying the UTC offset during DST. If unspecified and any other DST information is specified, it is assumed to be the STD offset +1 hour.
  • start

    A relativedelta.relativedelta object or equivalent specifying the time and time of year that daylight savings time starts. To specify, for example, that DST starts at 2AM on the 2nd Sunday in March, pass:

    relativedelta(hours=2, month=3, day=1, weekday=SU(+2))

    If unspecified and any other DST information is specified, the default value is 2 AM on the first Sunday in April.

  • end – A relativedelta.relativedelta object or equivalent representing the time and time of year that daylight savings time ends, with the same specification method as in start. One note is that this should point to the first time in the standard zone, so if a transition occurs at 2AM in the DST zone and the clocks are set back 1 hour to 1AM, set the hours parameter to +1.

Examples:

>>> tzstr('EST5EDT') == tzrange("EST", -18000, "EDT")
True

>>> from dateutil.relativedelta import *
>>> range1 = tzrange("EST", -18000, "EDT")
>>> range2 = tzrange("EST", -18000, "EDT", -14400,
...                  relativedelta(hours=+2, month=4, day=1,
...                                weekday=SU(+1)),
...                  relativedelta(hours=+1, month=10, day=31,
...                                weekday=SU(-1)))
>>> tzstr('EST5EDT') == range1 == range2
True
transitions(year)[source]

For a given year, get the DST on and off transition times, expressed always on the standard time side. For zones with no transitions, this function returns None.

Parameters:year – The year whose transitions you would like to query.
Returns:Returns a tuple of datetime.datetime objects, (dston, dstoff) for zones with an annual DST transition, or None for fixed offset zones.
class dateutil.tz.tzstr(s, posix_offset=False)[source]

tzstr objects are time zone objects specified by a time-zone string as it would be passed to a TZ variable on POSIX-style systems (see the GNU C Library: TZ Variable for more details).

There is one notable exception, which is that POSIX-style time zones use an inverted offset format, so normally GMT+3 would be parsed as an offset 3 hours behind GMT. The tzstr time zone object will parse this as an offset 3 hours ahead of GMT. If you would like to maintain the POSIX behavior, pass a True value to posix_offset.

The tzrange object provides the same functionality, but is specified using relativedelta.relativedelta objects. rather than strings.

Parameters:
  • s – A time zone string in TZ variable format. This can be a bytes (2.x: str), str (2.x: unicode) or a stream emitting unicode characters (e.g. StringIO).
  • posix_offset – Optional. If set to True, interpret strings such as GMT+3 or UTC+3 as being 3 hours behind UTC rather than ahead, per the POSIX standard.

Caution

Prior to version 2.7.0, this function also supported time zones in the format:

  • EST5EDT,4,0,6,7200,10,0,26,7200,3600
  • EST5EDT,4,1,0,7200,10,-1,0,7200,3600

This format is non-standard and has been deprecated; this function will raise a DeprecatedTZFormatWarning until support is removed in a future version.

class dateutil.tz.tzical(fileobj)[source]

This object is designed to parse an iCalendar-style VTIMEZONE structure as set out in RFC 5545 Section 4.6.5 into one or more tzinfo objects.

Parameters:fileobj – A file or stream in iCalendar format, which should be UTF-8 encoded with CRLF endings.
get(tzid=None)[source]

Retrieve a datetime.tzinfo object by its tzid.

Parameters:tzid – If there is exactly one time zone available, omitting tzid or passing None value returns it. Otherwise a valid key (which can be retrieved from 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 datetime.tzinfo object representing the relevant time zone or None if the tzid was not found.
keys()[source]

Retrieves the available time zones as a list.

dateutil.tz.enfold(dt, fold=1)[source]

Provides a unified interface for assigning the fold attribute to datetimes both before and after the implementation of PEP-495.

Parameters:fold – The value for the fold attribute in the returned datetime. This should be either 0 or 1.
Returns: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 datetime.datetime with the fold attribute added, if fold is 1.

New in version 2.6.0.

dateutil.tz.datetime_ambiguous(dt, tz=None)[source]

Given a datetime and a time zone, determine whether or not a given datetime is ambiguous (i.e if there are two times differentiated only by their DST status).

Parameters:
  • dt – A datetime.datetime (whose time zone will be ignored if tz is provided.)
  • tz – A datetime.tzinfo with support for the fold attribute. If None or not provided, the datetime’s own time zone will be used.
Returns:

Returns a boolean value whether or not the “wall time” is ambiguous in tz.

New in version 2.6.0.

dateutil.tz.datetime_exists(dt, tz=None)[source]

Given a datetime and a time zone, determine whether or not a given datetime would fall in a gap.

Parameters:
  • dt – A datetime.datetime (whose time zone will be ignored if tz is provided.)
  • tz – A datetime.tzinfo with support for the fold attribute. If None or not provided, the datetime’s own time zone will be used.
Returns:

Returns a boolean value whether or not the “wall time” exists in tz.

..versionadded:: 2.7.0

dateutil.tz.resolve_imaginary(dt)[source]

Given a datetime that may be imaginary, return an existing datetime.

This function assumes that an imaginary datetime represents what the wall time would be in a zone had the offset transition not occurred, so it will always fall forward by the transition’s change in offset.

..doctest::
>>> from dateutil import tz
>>> from datetime import datetime
>>> NYC = tz.gettz('America/New_York')
>>> print(tz.resolve_imaginary(datetime(2017, 3, 12, 2, 30, tzinfo=NYC)))
2017-03-12 03:30:00-04:00
>>> KIR = tz.gettz('Pacific/Kiritimati')
>>> print(tz.resolve_imaginary(datetime(1995, 1, 1, 12, 30, tzinfo=KIR)))
1995-01-02 12:30:00+14:00

As a note, datetime.astimezone() is guaranteed to produce a valid, existing datetime, so a round-trip to and from UTC is sufficient to get an extant datetime, however, this generally “falls back” to an earlier time rather than falling forward to the STD side (though no guarantees are made about this behavior).

Parameters:dt – A datetime.datetime which may or may not exist.
Returns:Returns an existing datetime.datetime. If dt was not imaginary, the datetime returned is guaranteed to be the same object passed to the function.

..versionadded:: 2.7.0

dateutil.tz.UTC = tzutc()

Convenience constant providing a tzutc() instance

New in version 2.7.0.

exception dateutil.tz.DeprecatedTzFormatWarning[source]

Warning raised when time zones are parsed from deprecated formats.