What's new in 2.1.2 (October 26, 2023)

.. _whatsnew_212:

These are the changes in pandas 2.1.2. See :ref:release for a full changelog including other versions of pandas.

.. --------------------------------------------------------------------------- .. _whatsnew_212.deprecations:

Deprecations


- Reverted deprecation of ``fill_method=None`` in :meth:`DataFrame.pct_change`, :meth:`Series.pct_change`, :meth:`DataFrameGroupBy.pct_change`, and :meth:`SeriesGroupBy.pct_change`; the values ``'backfill'``, ``'bfill'``, ``'pad'``, and ``'ffill'`` are still deprecated (:issue:`53491`)

.. ---------------------------------------------------------------------------
.. _whatsnew_212.regressions:

Fixed regressions

Fixed regression in :meth:DataFrame.join where result has missing values and dtype is arrow backed string (:issue:55348)
Fixed regression in :meth:~DataFrame.rolling where non-nanosecond index or on column would produce incorrect results (:issue:55026, :issue:55106, :issue:55299)
Fixed regression in :meth:DataFrame.resample which was extrapolating back to origin when origin was outside its bounds (:issue:55064)
Fixed regression in :meth:DataFrame.sort_index which was not sorting correctly when the index was a sliced :class:MultiIndex (:issue:55379)
Fixed regression in :meth:DataFrameGroupBy.agg and :meth:SeriesGroupBy.agg where if the option compute.use_numba was set to True, groupby methods not supported by the numba engine would raise a TypeError (:issue:55520)
Fixed performance regression with wide DataFrames, typically involving methods where all columns were accessed individually (:issue:55256, :issue:55245)
Fixed regression in :func:merge_asof raising TypeError for by with datetime and timedelta dtypes (:issue:55453)
Fixed regression in :func:read_parquet when reading a file with a string column consisting of more than 2 GB of string data and using the "string" dtype (:issue:55606)
Fixed regression in :meth:DataFrame.to_sql not roundtripping datetime columns correctly for sqlite when using detect_types (:issue:55554)
Fixed regression in construction of certain DataFrame or Series subclasses (:issue:54922)

.. --------------------------------------------------------------------------- .. _whatsnew_212.bug_fixes:

Bug fixes

- Fixed bug in :class:`.DataFrameGroupBy` reductions not preserving object dtype when ``infer_string`` is set (:issue:`55620`)
- Fixed bug in :meth:`.SeriesGroupBy.value_counts` returning incorrect dtype for string columns (:issue:`55627`)
- Fixed bug in :meth:`Categorical.equals` if other has arrow backed string dtype (:issue:`55364`)
- Fixed bug in :meth:`DataFrame.__setitem__` not inferring string dtype for zero-dimensional array with ``infer_string=True`` (:issue:`55366`)
- Fixed bug in :meth:`DataFrame.idxmin` and :meth:`DataFrame.idxmax` raising for arrow dtypes (:issue:`55368`)
- Fixed bug in :meth:`DataFrame.interpolate` raising incorrect error message (:issue:`55347`)
- Fixed bug in :meth:`Index.insert` raising when inserting ``None`` into :class:`Index` with ``dtype="string[pyarrow_numpy]"`` (:issue:`55365`)
- Fixed bug in :meth:`Series.all`  and :meth:`Series.any` not treating missing values correctly for ``dtype="string[pyarrow_numpy]"`` (:issue:`55367`)
- Fixed bug in :meth:`Series.floordiv` for :class:`ArrowDtype` (:issue:`55561`)
- Fixed bug in :meth:`Series.mode` not sorting values for arrow backed string dtype (:issue:`55621`)
- Fixed bug in :meth:`Series.rank` for ``string[pyarrow_numpy]`` dtype (:issue:`55362`)
- Fixed bug in :meth:`Series.str.extractall` for :class:`ArrowDtype` dtype being converted to object (:issue:`53846`)
- Fixed bug where PDEP-6 warning about setting an item of an incompatible dtype was being shown when creating a new conditional column (:issue:`55025`)
- Silence ``Period[B]`` warnings introduced by :issue:`53446` during normal plotting activity (:issue:`55138`)
- Fixed bug in :class:`Series` constructor not inferring string dtype when ``NA`` is the first value and ``infer_string`` is set (:issue:` 55655`)

.. ---------------------------------------------------------------------------
.. _whatsnew_212.other:

Other
~~~~~
- Fixed non-working installation of optional dependency group ``output_formatting``. Replacing underscore ``_`` with a dash ``-`` fixes broken dependency resolution. A correct way to use now is ``pip install pandas[output-formatting]``.
-

.. ---------------------------------------------------------------------------
.. _whatsnew_212.contributors:

Contributors

.. contributors:: v2.1.1..v2.1.2