BUG/API: Index creation with different tz coerces DatetimeIndex

pandas-dev · Dec 8, 2015 · 162bd1d · 162bd1d
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diff --git a/doc/source/whatsnew/v0.18.0.txt b/doc/source/whatsnew/v0.18.0.txt
@@ -187,7 +187,6 @@ Bug Fixes
 - Bug in timezone info lost when broadcasting scalar datetime to ``DataFrame`` (:issue:`11682`)
 
 
-
 - Bug in parsing timezone offset strings with non-zero minutes (:issue:`11708`)
 
 
@@ -197,3 +196,5 @@ Bug Fixes
 - Bug in ``pd.rolling_median`` where memory allocation failed even with sufficient memory (:issue:`11696`)
 
 - Bug in ``df.replace`` while replacing value in mixed dtype ``Dataframe`` (:issue:`11698`)
+- Bug in ``Index`` creation from ``Timestamp`` with mixed tz coerces to UTC (:issue:`11488`)
+
diff --git a/pandas/core/index.py b/pandas/core/index.py
@@ -179,8 +179,13 @@ def __new__(cls, data=None, dtype=None, copy=False, name=None, fastpath=False,
                 elif inferred != 'string':
                     if (inferred.startswith('datetime') or
                         tslib.is_timestamp_array(subarr)):
-                        from pandas.tseries.index import DatetimeIndex
-                        return DatetimeIndex(subarr, copy=copy, name=name, **kwargs)
+
+                        if (lib.is_datetime_with_singletz_array(subarr) or
+                            'tz' in kwargs):
+                            # only when subarr has the same tz
+                            from pandas.tseries.index import DatetimeIndex
+                            return DatetimeIndex(subarr, copy=copy, name=name, **kwargs)
+
                     elif (inferred.startswith('timedelta') or
                           lib.is_timedelta_array(subarr)):
                         from pandas.tseries.tdi import TimedeltaIndex

diff --git a/pandas/src/inference.pyx b/pandas/src/inference.pyx
@@ -1,6 +1,6 @@
 import sys
 cimport util
-from tslib import NaT
+from tslib import NaT, get_timezone
 from datetime import datetime, timedelta
 iNaT = util.get_nat()
 
@@ -431,6 +431,35 @@ def is_datetime64_array(ndarray values):
             return False
     return null_count != n
 
+
+cpdef is_datetime_with_singletz_array(ndarray[object] values):
+    """
+    Check values have the same tzinfo attribute.
+    Doesn't check values are datetime-like types.
+    """
+
+    cdef Py_ssize_t i, j, n = len(values)
+    cdef object base_val, base_tz, val, tz
+
+    if n == 0:
+        return False
+
+    for i in range(n):
+        base_val = values[i]
+        if base_val is not NaT:
+            base_tz = get_timezone(getattr(base_val, 'tzinfo', None))
+
+            for j in range(i, n):
+                val = values[j]
+                if val is not NaT:
+                    tz = getattr(val, 'tzinfo', None)
+                    if base_tz != tz and base_tz != get_timezone(tz):
+                        return False
+            break
+
+    return True
+
+
 def is_timedelta_array(ndarray values):
     cdef Py_ssize_t i, null_count = 0, n = len(values)
     cdef object v

diff --git a/pandas/tests/test_index.py b/pandas/tests/test_index.py
@@ -3493,6 +3493,189 @@ def test_construction_with_alt(self):
     def test_pickle_compat_construction(self):
         pass
 
+    def test_construction_index_with_mixed_timezones(self):
+        # GH 11488
+        # no tz results in DatetimeIndex
+        result = Index([Timestamp('2011-01-01'), Timestamp('2011-01-02')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01'), Timestamp('2011-01-02')], name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNone(result.tz)
+
+        # same tz results in DatetimeIndex
+        result = Index([Timestamp('2011-01-01 10:00', tz='Asia/Tokyo'),
+                        Timestamp('2011-01-02 10:00', tz='Asia/Tokyo')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01 10:00'), Timestamp('2011-01-02 10:00')], tz='Asia/Tokyo', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNotNone(result.tz)
+        self.assertEqual(result.tz, exp.tz)
+
+        # same tz results in DatetimeIndex (DST)
+        result = Index([Timestamp('2011-01-01 10:00', tz='US/Eastern'),
+                        Timestamp('2011-08-01 10:00', tz='US/Eastern')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01 10:00'), Timestamp('2011-08-01 10:00')],
+                            tz='US/Eastern', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNotNone(result.tz)
+        self.assertEqual(result.tz, exp.tz)
+
+        # different tz results in Index(dtype=object)
+        result = Index([Timestamp('2011-01-01 10:00'), Timestamp('2011-01-02 10:00', tz='US/Eastern')], name='idx')
+        exp = Index([Timestamp('2011-01-01 10:00'), Timestamp('2011-01-02 10:00', tz='US/Eastern')],
+                    dtype='object', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertFalse(isinstance(result, DatetimeIndex))
+
+        result = Index([Timestamp('2011-01-01 10:00', tz='Asia/Tokyo'),
+                        Timestamp('2011-01-02 10:00', tz='US/Eastern')], name='idx')
+        exp = Index([Timestamp('2011-01-01 10:00', tz='Asia/Tokyo'),
+                     Timestamp('2011-01-02 10:00', tz='US/Eastern')],
+                    dtype='object', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertFalse(isinstance(result, DatetimeIndex))
+
+        # passing tz results in DatetimeIndex
+        result = Index([Timestamp('2011-01-01 10:00'), Timestamp('2011-01-02 10:00', tz='US/Eastern')],
+                        tz='Asia/Tokyo', name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01 19:00'), Timestamp('2011-01-03 00:00')],
+                            tz='Asia/Tokyo', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+
+        # length = 1
+        result = Index([Timestamp('2011-01-01')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01')], name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNone(result.tz)
+
+        # length = 1 with tz
+        result = Index([Timestamp('2011-01-01 10:00', tz='Asia/Tokyo')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01 10:00')], tz='Asia/Tokyo', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNotNone(result.tz)
+        self.assertEqual(result.tz, exp.tz)
+
+    def test_construction_index_with_mixed_timezones_with_NaT(self):
+        # GH 11488
+        result = Index([pd.NaT, Timestamp('2011-01-01'),
+                        pd.NaT, Timestamp('2011-01-02')], name='idx')
+        exp = DatetimeIndex([pd.NaT, Timestamp('2011-01-01'),
+                             pd.NaT, Timestamp('2011-01-02')], name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNone(result.tz)
+
+        # same tz results in DatetimeIndex
+        result = Index([pd.NaT, Timestamp('2011-01-01 10:00', tz='Asia/Tokyo'),
+                        pd.NaT, Timestamp('2011-01-02 10:00', tz='Asia/Tokyo')], name='idx')
+        exp = DatetimeIndex([pd.NaT, Timestamp('2011-01-01 10:00'),
+                             pd.NaT, Timestamp('2011-01-02 10:00')], tz='Asia/Tokyo', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNotNone(result.tz)
+        self.assertEqual(result.tz, exp.tz)
+
+        # same tz results in DatetimeIndex (DST)
+        result = Index([Timestamp('2011-01-01 10:00', tz='US/Eastern'),
+                        pd.NaT, Timestamp('2011-08-01 10:00', tz='US/Eastern')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01 10:00'), pd.NaT, Timestamp('2011-08-01 10:00')],
+                            tz='US/Eastern', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNotNone(result.tz)
+        self.assertEqual(result.tz, exp.tz)
+
+        # different tz results in Index(dtype=object)
+        result = Index([pd.NaT, Timestamp('2011-01-01 10:00'),
+                        pd.NaT, Timestamp('2011-01-02 10:00', tz='US/Eastern')], name='idx')
+        exp = Index([pd.NaT, Timestamp('2011-01-01 10:00'),
+                     pd.NaT, Timestamp('2011-01-02 10:00', tz='US/Eastern')],
+                    dtype='object', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertFalse(isinstance(result, DatetimeIndex))
+
+        result = Index([pd.NaT, Timestamp('2011-01-01 10:00', tz='Asia/Tokyo'),
+                        pd.NaT, Timestamp('2011-01-02 10:00', tz='US/Eastern')], name='idx')
+        exp = Index([pd.NaT, Timestamp('2011-01-01 10:00', tz='Asia/Tokyo'),
+                     pd.NaT, Timestamp('2011-01-02 10:00', tz='US/Eastern')],
+                    dtype='object', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertFalse(isinstance(result, DatetimeIndex))
+
+        # passing tz results in DatetimeIndex
+        result = Index([pd.NaT, Timestamp('2011-01-01 10:00'),
+                        pd.NaT, Timestamp('2011-01-02 10:00', tz='US/Eastern')],
+                        tz='Asia/Tokyo', name='idx')
+        exp = DatetimeIndex([pd.NaT, Timestamp('2011-01-01 19:00'),
+                             pd.NaT, Timestamp('2011-01-03 00:00')],
+                            tz='Asia/Tokyo', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+
+        # all NaT
+        result = Index([pd.NaT, pd.NaT], name='idx')
+        exp = DatetimeIndex([pd.NaT, pd.NaT], name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNone(result.tz)
+
+        # all NaT with tz
+        result = Index([pd.NaT, pd.NaT], tz='Asia/Tokyo', name='idx')
+        exp = DatetimeIndex([pd.NaT, pd.NaT], tz='Asia/Tokyo', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+        self.assertIsNotNone(result.tz)
+        self.assertEqual(result.tz, exp.tz)
+
+    def test_construction_dti_with_mixed_timezones(self):
+        # GH 11488 (not changed, added explicit tests)
+
+        # no tz results in DatetimeIndex
+        result = DatetimeIndex([Timestamp('2011-01-01'), Timestamp('2011-01-02')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01'), Timestamp('2011-01-02')], name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+
+        # same tz results in DatetimeIndex
+        result = DatetimeIndex([Timestamp('2011-01-01 10:00', tz='Asia/Tokyo'),
+                                Timestamp('2011-01-02 10:00', tz='Asia/Tokyo')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01 10:00'), Timestamp('2011-01-02 10:00')], tz='Asia/Tokyo', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+
+        # same tz results in DatetimeIndex (DST)
+        result = DatetimeIndex([Timestamp('2011-01-01 10:00', tz='US/Eastern'),
+                                Timestamp('2011-08-01 10:00', tz='US/Eastern')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01 10:00'), Timestamp('2011-08-01 10:00')],
+                            tz='US/Eastern', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+
+        # different tz coerces tz-naive to tz-awareIndex(dtype=object)
+        result = DatetimeIndex([Timestamp('2011-01-01 10:00'),
+                                Timestamp('2011-01-02 10:00', tz='US/Eastern')], name='idx')
+        exp = DatetimeIndex([Timestamp('2011-01-01 05:00'), Timestamp('2011-01-02 10:00')],
+                            tz='US/Eastern', name='idx')
+        self.assert_index_equal(result, exp, exact=True)
+        self.assertTrue(isinstance(result, DatetimeIndex))
+
+        # tz mismatch affecting to tz-aware raises TypeError/ValueError
+        with tm.assertRaises(ValueError):
+            DatetimeIndex([Timestamp('2011-01-01 10:00', tz='Asia/Tokyo'),
+                           Timestamp('2011-01-02 10:00', tz='US/Eastern')], name='idx')
+
+        with tm.assertRaises(TypeError):
+            DatetimeIndex([Timestamp('2011-01-01 10:00'), Timestamp('2011-01-02 10:00', tz='US/Eastern')],
+                          tz='Asia/Tokyo', name='idx')
+
+        with tm.assertRaises(ValueError):
+            DatetimeIndex([Timestamp('2011-01-01 10:00', tz='Asia/Tokyo'),
+                           Timestamp('2011-01-02 10:00', tz='US/Eastern')], tz='US/Eastern', name='idx')
+
     def test_get_loc(self):
         idx = pd.date_range('2000-01-01', periods=3)
 

diff --git a/pandas/util/testing.py b/pandas/util/testing.py
@@ -718,7 +718,11 @@ def assert_attr_equal(attr, left, right, obj='Attributes'):
         # np.nan
         return True
 
-    result = left_attr == right_attr
+    try:
+        result = left_attr == right_attr
+    except TypeError:
+        # datetimetz on rhs may raise TypeError
+        result = False
     if not isinstance(result, bool):
         result = result.all()