v2.1.2.rst

What's new in 2.1.2 (October 25, 2023)

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

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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`)

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`)

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`)

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].

Contributors