Revert set_index inspection/error handling for 0.24.1

doc/source/index.rst.template

@@ -39,7 +39,7 @@ See the :ref:`overview` for more detail about what's in the library.
 {% endif %}
 
     {% if not single_doc -%}
-    What's New in 0.24.0 <whatsnew/v0.24.0>
+    What's New in 0.24.1 <whatsnew/v0.24.1>
     install
     getting_started/index
     user_guide/index

doc/source/user_guide/io.rst

@@ -989,6 +989,36 @@ a single date rather than the entire array.
 
    os.remove('tmp.csv')
 
+
+.. _io.csv.mixed_timezones:
+
+Parsing a CSV with mixed Timezones
+++++++++++++++++++++++++++++++++++
+
+Pandas cannot natively represent a column or index with mixed timezones. If your CSV
+file contains columns with a mixture of timezones, the default result will be
+an object-dtype column with strings, even with ``parse_dates``.
+
+
+.. ipython:: python
+
+   content = """\
+   a
+   2000-01-01T00:00:00+05:00
+   2000-01-01T00:00:00+06:00"""
+   df = pd.read_csv(StringIO(content), parse_dates=['a'])
+   df['a']
+
+To parse the mixed-timezone values as a datetime column, pass a partially-applied
+:func:`to_datetime` with ``utc=True`` as the ``date_parser``.
+
+.. ipython:: python
+
+   df = pd.read_csv(StringIO(content), parse_dates=['a'],
+                    date_parser=lambda col: pd.to_datetime(col, utc=True))
+   df['a']
+
+
 .. _io.dayfirst:
 
 

doc/source/whatsnew/v0.24.0.rst

@@ -6,7 +6,8 @@ What's New in 0.24.0 (January 25, 2019)
 .. warning::
 
    The 0.24.x series of releases will be the last to support Python 2. Future feature
-   releases will support Python 3 only. See :ref:`install.dropping-27` for more.
+   releases will support Python 3 only. See :ref:`install.dropping-27` for more
+   details.
 
 {{ header }}
 
@@ -244,7 +245,7 @@ the new extension arrays that back interval and period data.
 Joining with two multi-indexes
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-:func:`DataFrame.merge` and :func:`DataFrame.join` can now be used to join multi-indexed ``Dataframe`` instances on the overlaping index levels (:issue:`6360`)
+:func:`DataFrame.merge` and :func:`DataFrame.join` can now be used to join multi-indexed ``Dataframe`` instances on the overlapping index levels (:issue:`6360`)
 
 See the :ref:`Merge, join, and concatenate
 <merging.Join_with_two_multi_indexes>` documentation section.
@@ -647,6 +648,52 @@ that the dates have been converted to UTC
     pd.to_datetime(["2015-11-18 15:30:00+05:30",
                     "2015-11-18 16:30:00+06:30"], utc=True)
 
+
+.. _whatsnew_0240.api_breaking.read_csv_mixed_tz:
+
+Parsing mixed-timezones with :func:`read_csv`
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+:func:`read_csv` no longer silently converts mixed-timezone columns to UTC (:issue:`24987`).
+
+*Previous Behavior*
+
+.. code-block:: python
+
+   >>> import io
+   >>> content = """\
+   ... a
+   ... 2000-01-01T00:00:00+05:00
+   ... 2000-01-01T00:00:00+06:00"""
+   >>> df = pd.read_csv(io.StringIO(content), parse_dates=['a'])
+   >>> df.a
+   0   1999-12-31 19:00:00
+   1   1999-12-31 18:00:00
+   Name: a, dtype: datetime64[ns]
+
+*New Behavior*
+
+.. ipython:: python
+
+   import io
+   content = """\
+   a
+   2000-01-01T00:00:00+05:00
+   2000-01-01T00:00:00+06:00"""
+   df = pd.read_csv(io.StringIO(content), parse_dates=['a'])
+   df.a
+
+As can be seen, the ``dtype`` is object; each value in the column is a string.
+To convert the strings to an array of datetimes, the ``date_parser`` argument
+
+.. ipython:: python
+
+   df = pd.read_csv(io.StringIO(content), parse_dates=['a'],
+                    date_parser=lambda col: pd.to_datetime(col, utc=True))
+   df.a
+
+See :ref:`whatsnew_0240.api.timezone_offset_parsing` for more.
+
 .. _whatsnew_0240.api_breaking.period_end_time:
 
 Time values in ``dt.end_time`` and ``to_timestamp(how='end')``
@@ -1148,8 +1195,6 @@ Other API Changes
 - :class:`pandas.io.formats.style.Styler` supports a ``number-format`` property when using :meth:`~pandas.io.formats.style.Styler.to_excel` (:issue:`22015`)
 - :meth:`DataFrame.corr` and :meth:`Series.corr` now raise a ``ValueError`` along with a helpful error message instead of a ``KeyError`` when supplied with an invalid method (:issue:`22298`)
 - :meth:`shift` will now always return a copy, instead of the previous behaviour of returning self when shifting by 0 (:issue:`22397`)
-- :meth:`DataFrame.set_index` now gives a better (and less frequent) KeyError, raises a ``ValueError`` for incorrect types,
-  and will not fail on duplicate column names with ``drop=True``. (:issue:`22484`)
 - Slicing a single row of a DataFrame with multiple ExtensionArrays of the same type now preserves the dtype, rather than coercing to object (:issue:`22784`)
 - :class:`DateOffset` attribute `_cacheable` and method `_should_cache` have been removed (:issue:`23118`)
 - :meth:`Series.searchsorted`, when supplied a scalar value to search for, now returns a scalar instead of an array (:issue:`23801`).

doc/source/whatsnew/v0.24.1.rst

@@ -13,61 +13,66 @@ Whats New in 0.24.1 (February XX, 2019)
 {{ header }}
 
 These are the changes in pandas 0.24.1. See :ref:`release` for a full changelog
-including other versions of pandas.
+including other versions of pandas. See :ref:`whatsnew_0240` for the 0.24.0 changelog.
 
+.. _whatsnew_0241.api:
 
-.. _whatsnew_0241.enhancements:
+API Changes
+~~~~~~~~~~~
 
-Enhancements
-^^^^^^^^^^^^
+Changing the ``sort`` parameter for :class:`Index` set operations
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+The default ``sort`` value for :meth:`Index.union` has changed from ``True`` to ``None`` (:issue:`24959`).
+The default *behavior*, however, remains the same: the result is sorted, unless
 
-.. _whatsnew_0241.bug_fixes:
+1. ``self`` and ``other`` are identical
+2. ``self`` or ``other`` is empty
+3. ``self`` or ``other`` contain values that can not be compared (a ``RuntimeWarning`` is raised).
 
-Bug Fixes
-~~~~~~~~~
+This change will allow ``sort=True`` to mean "always sort" in a future release.
 
-**Conversion**
+The same change applies to :meth:`Index.difference` and :meth:`Index.symmetric_difference`, which
+would not sort the result when the values could not be compared.
 
--
--
--
+The `sort` option for :meth:`Index.intersection` has changed in three ways.
 
-**Indexing**
+1. The default has changed from ``True`` to ``False``, to restore the
+   pandas 0.23.4 and earlier behavior of not sorting by default.
+2. The behavior of ``sort=True`` can now be obtained with ``sort=None``.
+   This will sort the result only if the values in ``self`` and ``other``
+   are not identical.
+3. The value ``sort=True`` is no longer allowed. A future version of pandas
+   will properly support ``sort=True`` meaning "always sort".
 
--
--
--
+.. _whatsnew_0241.regressions:
 
-**I/O**
+Fixed Regressions
+~~~~~~~~~~~~~~~~~
 
--
--
--
+- Bug in :meth:`DataFrame.itertuples` with ``records`` orient raising an ``AttributeError`` when the ``DataFrame`` contained more than 255 columns (:issue:`24939`)
+- Bug in :meth:`DataFrame.itertuples` orient converting integer column names to strings prepended with an underscore (:issue:`24940`)
+- Fixed regression in :func:`read_sql` when passing certain queries with MySQL/pymysql (:issue:`24988`).
+- Fixed regression in :class:`Index.intersection` incorrectly sorting the values by default (:issue:`24959`).
+- Fixed regression in :func:`merge` when merging an empty ``DataFrame`` with multiple timezone-aware columns on one of the timezone-aware columns (:issue:`25014`).
+- Fixed regression in :meth:`Series.rename_axis` and :meth:`DataFrame.rename_axis` where passing ``None`` failed to remove the axis name (:issue:`25034`)
 
-**Categorical**
+**Timedelta**
 
--
--
--
+- Bug in :func:`to_timedelta` with `box=False` incorrectly returning a ``datetime64`` object instead of a ``timedelta64`` object (:issue:`24961`)
 
-**Timezones**
+**Reshaping**
 
--
--
--
+- Bug in :meth:`DataFrame.groupby` with :class:`Grouper` when there is a time change (DST) and grouping frequency is ``'1d'`` (:issue:`24972`)
 
-**Timedelta**
+**Visualization**
 
--
--
--
+- Fixed the warning for implicitly registered matplotlib converters not showing. See :ref:`whatsnew_0211.converters` for more (:issue:`24963`).
 
 
 **Other**
 
--
--
+- Fixed AttributeError when printing a DataFrame's HTML repr after accessing the IPython config object (:issue:`25036`)
 
 .. _whatsnew_0.241.contributors:
 

doc/source/whatsnew/v0.24.2.rst

@@ -0,0 +1,99 @@
+:orphan:
+
+.. _whatsnew_0242:
+
+Whats New in 0.24.2 (February XX, 2019)
+---------------------------------------
+
+.. warning::
+
+   The 0.24.x series of releases will be the last to support Python 2. Future feature
+   releases will support Python 3 only. See :ref:`install.dropping-27` for more.
+
+{{ header }}
+
+These are the changes in pandas 0.24.2. See :ref:`release` for a full changelog
+including other versions of pandas.
+
+.. _whatsnew_0242.regressions:
+
+Fixed Regressions
+^^^^^^^^^^^^^^^^^
+
+-
+-
+-
+
+.. _whatsnew_0242.enhancements:
+
+Enhancements
+^^^^^^^^^^^^
+
+-
+-
+
+.. _whatsnew_0242.bug_fixes:
+
+Bug Fixes
+~~~~~~~~~
+
+**Conversion**
+
+-
+-
+-
+
+**Indexing**
+
+-
+-
+-
+
+**I/O**
+
+-
+-
+-
+
+**Categorical**
+
+-
+-
+-
+
+**Timezones**
+
+-
+-
+-
+
+**Timedelta**
+
+-
+-
+-
+
+**Reshaping**
+
+-
+-
+-
+
+**Visualization**
+
+-
+-
+-
+
+**Other**
+
+-
+-
+-
+
+.. _whatsnew_0.242.contributors:
+
+Contributors
+~~~~~~~~~~~~
+
+.. contributors:: v0.24.1..v0.24.2

pandas/_libs/lib.pyx

@@ -231,10 +231,11 @@ def fast_unique_multiple(list arrays, sort: bool=True):
             if val not in table:
                 table[val] = stub
                 uniques.append(val)
-    if sort:
+    if sort is None:
         try:
             uniques.sort()
         except Exception:
+            # TODO: RuntimeWarning?
             pass
 
     return uniques

pandas/core/arrays/numpy_.py

@@ -222,7 +222,7 @@ def __getitem__(self, item):
             item = item._ndarray
 
         result = self._ndarray[item]
-        if not lib.is_scalar(result):
+        if not lib.is_scalar(item):
             result = type(self)(result)
         return result