v0.23.1.txt

.. _whatsnew_0231:

v0.23.1
-------

This is a minor bug-fix release in the 0.23.x series and includes some small regression fixes
and bug fixes. We recommend that all users upgrade to this version.

.. contents:: What's new in v0.23.1
    :local:
    :backlinks: none

.. _whatsnew_0231.enhancements:

New features
~~~~~~~~~~~~

- :meth:`Index.droplevel` is now implemented also for flat indexes, for compatibility with MultiIndex (:issue:`21115`)


.. _whatsnew_0231.deprecations:

Deprecations
~~~~~~~~~~~~

-
-

.. _whatsnew_0231.performance:

Performance Improvements
~~~~~~~~~~~~~~~~~~~~~~~~

- Improved performance of :meth:`CategoricalIndex.is_monotonic_increasing`, :meth:`CategoricalIndex.is_monotonic_decreasing` and :meth:`CategoricalIndex.is_monotonic` (:issue:`21025`)
- Improved performance of :meth:`CategoricalIndex.is_unique` (:issue:`21107`)
-
-

Documentation Changes
~~~~~~~~~~~~~~~~~~~~~

-
-

.. _whatsnew_0231.bug_fixes:

Bug Fixes
~~~~~~~~~

Groupby/Resample/Rolling
^^^^^^^^^^^^^^^^^^^^^^^^

- Bug in :func:`DataFrame.agg` where applying multiple aggregation functions to a :class:`DataFrame` with duplicated column names would cause a stack overflow (:issue:`21063`)
- Bug in :func:`pandas.core.groupby.GroupBy.ffill` and :func:`pandas.core.groupby.GroupBy.bfill` where the fill within a grouping would not always be applied as intended due to the implementations' use of a non-stable sort (:issue:`21207`)
- Bug in :func:`pandas.core.groupby.GroupBy.rank` where results did not scale to 100% when specifying ``method='dense'`` and ``pct=True``

Strings
^^^^^^^

- Bug in :meth:`Series.str.replace()` where the method throws `TypeError` on Python 3.5.2 (:issue: `21078`)

Timedelta
^^^^^^^^^
- Bug in :class:`Timedelta`: where passing a float with a unit would prematurely round the float precision (:issue: `14156`)

Categorical
^^^^^^^^^^^

- Bug in :func:`pandas.util.testing.assert_index_equal` which raised ``AssertionError`` incorrectly, when comparing two :class:`CategoricalIndex` objects with param ``check_categorical=False`` (:issue:`19776`)
- Bug in :meth:`Categorical.fillna` incorrectly raising a ``TypeError`` when `value` the individual categories are iterable and `value` is an iterable (:issue:`21097`, :issue:`19788`)

Sparse
^^^^^^

- Bug in :attr:`SparseArray.shape` which previously only returned the shape :attr:`SparseArray.sp_values` (:issue:`21126`)

Conversion
^^^^^^^^^^

-
-

Indexing
^^^^^^^^

- Bug in :meth:`Series.reset_index` where appropriate error was not raised with an invalid level name (:issue:`20925`)
- Bug in :func:`interval_range` when ``start``/``periods`` or ``end``/``periods`` are specified with float ``start`` or ``end`` (:issue:`21161`)
- Bug in :meth:`MultiIndex.set_names` where error raised for a ``MultiIndex`` with ``nlevels == 1`` (:issue:`21149`)
- Bug in :attr:`DatetimeIndex.date` where an incorrect date is returned when the input date has a non-UTC timezone (:issue:`21230`)
- Bug in :class:`IntervalIndex` constructors where creating an ``IntervalIndex`` from categorical data was not fully supported (:issue:`21243`, issue:`21253`)
-

I/O
^^^

- Bug in IO methods specifying ``compression='zip'`` which produced uncompressed zip archives (:issue:`17778`, :issue:`21144`)
- Bug in :meth:`DataFrame.to_stata` which prevented exporting DataFrames to buffers and most file-like objects (:issue:`21041`)
-

Plotting
^^^^^^^^

-
-

Reshaping
^^^^^^^^^

- Bug in :func:`concat` where error was raised in concatenating :class:`Series` with numpy scalar and tuple names (:issue:`21015`)
-

Other
^^^^^

- Tab completion on :class:`Index` in IPython no longer outputs deprecation warnings (:issue:`21125`)
- Bug preventing pandas from being importable with -OO optimization (:issue:`21071`)