ENH: Support datetime.timezone objects (#25065)

Author: mroeschke

doc/source/user_guide/timeseries.rst

@@ -2149,12 +2149,9 @@ Time Zone Handling
 ------------------
 
 pandas provides rich support for working with timestamps in different time
-zones using the ``pytz`` and ``dateutil`` libraries.
+zones using the ``pytz`` and ``dateutil`` libraries or class:`datetime.timezone`
+objects from the standard library.
 
-.. note::
-
-    pandas does not yet support ``datetime.timezone`` objects from the standard
-    library.
 
 Working with Time Zones
 ~~~~~~~~~~~~~~~~~~~~~~~
@@ -2197,6 +2194,15 @@ To return ``dateutil`` time zone objects, append ``dateutil/`` before the string
                            tz=dateutil.tz.tzutc())
    rng_utc.tz
 
+.. versionadded:: 0.25.0
+
+.. ipython:: python
+
+   # datetime.timezone
+   rng_utc = pd.date_range('3/6/2012 00:00', periods=3, freq='D',
+                           tz=datetime.timezone.utc)
+   rng_utc.tz
+
 Note that the ``UTC`` time zone is a special case in ``dateutil`` and should be constructed explicitly
 as an instance of ``dateutil.tz.tzutc``. You can also construct other time
 zones objects explicitly first.

doc/source/whatsnew/v0.25.0.rst

@@ -28,6 +28,7 @@ Other Enhancements
 - :meth:`DatetimeIndex.union` now supports the ``sort`` argument. The behaviour of the sort parameter matches that of :meth:`Index.union` (:issue:`24994`)
 - :meth:`DataFrame.rename` now supports the ``errors`` argument to raise errors when attempting to rename nonexistent keys (:issue:`13473`)
 - :class:`RangeIndex` has gained :attr:`~RangeIndex.start`, :attr:`~RangeIndex.stop`, and :attr:`~RangeIndex.step` attributes (:issue:`25710`)
+- :class:`datetime.timezone` objects are now supported as arguments to timezone methods and constructors (:issue:`25065`)
 
 .. _whatsnew_0250.api_breaking:
 

pandas/_libs/tslibs/timezones.pyx

@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from datetime import timezone
 
 # dateutil compat
 from dateutil.tz import (
@@ -23,11 +24,12 @@ from pandas._libs.tslibs.util cimport (
     is_string_object, is_integer_object, get_nat)
 
 cdef int64_t NPY_NAT = get_nat()
+cdef object utc_stdlib = timezone.utc
 
 # ----------------------------------------------------------------------
 
 cpdef inline bint is_utc(object tz):
-    return tz is UTC or isinstance(tz, _dateutil_tzutc)
+    return tz is UTC or tz is utc_stdlib or isinstance(tz, _dateutil_tzutc)
 
 
 cdef inline bint is_tzlocal(object tz):
@@ -167,6 +169,8 @@ cdef inline bint is_fixed_offset(object tz):
             return 1
         else:
             return 0
+    # This also implicitly accepts datetime.timezone objects which are
+    # considered fixed
     return 1
 
 

pandas/conftest.py

@@ -1,4 +1,4 @@
-from datetime import date, time, timedelta
+from datetime import date, time, timedelta, timezone
 from decimal import Decimal
 import os
 
@@ -247,13 +247,11 @@ def writable(request):
 
 @pytest.fixture(scope='module')
 def datetime_tz_utc():
-    from datetime import timezone
     return timezone.utc
 
 
 utc_objs = ['utc', 'dateutil/UTC', utc, tzutc()]
 if PY3:
-    from datetime import timezone
     utc_objs.append(timezone.utc)
 
 
@@ -366,7 +364,9 @@ def unique_nulls_fixture(request):
 
 TIMEZONES = [None, 'UTC', 'US/Eastern', 'Asia/Tokyo', 'dateutil/US/Pacific',
              'dateutil/Asia/Singapore', tzutc(), tzlocal(), FixedOffset(300),
-             FixedOffset(0), FixedOffset(-300)]
+             FixedOffset(0), FixedOffset(-300), timezone.utc,
+             timezone(timedelta(hours=1)),
+             timezone(timedelta(hours=-1), name='foo')]
 
 
 @td.parametrize_fixture_doc(str(TIMEZONES))

pandas/tests/indexes/datetimes/test_construction.py

@@ -119,7 +119,7 @@ def test_construction_with_alt_tz_localize(self, kwargs, tz_aware_fixture):
         i = pd.date_range('20130101', periods=5, freq='H', tz=tz)
         kwargs = {key: attrgetter(val)(i) for key, val in kwargs.items()}
 
-        if str(tz) in ('UTC', 'tzutc()'):
+        if str(tz) in ('UTC', 'tzutc()', 'UTC+00:00'):
             warn = None
         else:
             warn = FutureWarning

pandas/tests/indexes/test_base.py

@@ -416,9 +416,8 @@ def test_constructor_dtypes_datetime(self, tz_naive_fixture, attr, utc,
         # TODO(GH-24559): Remove the sys.modules and warnings
         # not sure what this is from. It's Py2 only.
         modules = [sys.modules['pandas.core.indexes.base']]
-
         if (tz_naive_fixture and attr == "asi8" and
-                str(tz_naive_fixture) not in ('UTC', 'tzutc()')):
+                str(tz_naive_fixture) not in ('UTC', 'tzutc()', 'UTC+00:00')):
             ex_warn = FutureWarning
         else:
             ex_warn = None