v1.3.4.rst

What's new in 1.3.4 (October 17, 2021)

These are the changes in pandas 1.3.4. See :ref:`release` for a full changelog including other versions of pandas.

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Fixed regressions

• Fixed regression in :meth:`DataFrame.convert_dtypes` incorrectly converts byte strings to strings (:issue:`43183`)
• Fixed regression in :meth:`.DataFrameGroupBy.agg` and :meth:`.SeriesGroupBy.agg` were failing silently with mixed data types along axis=1 and :class:`MultiIndex` (:issue:`43209`)
• Fixed regression in :func:`merge` with integer and NaN keys failing with outer merge (:issue:`43550`)
• Fixed regression in :meth:`DataFrame.corr` raising ValueError with method="spearman" on 32-bit platforms (:issue:`43588`)
• Fixed performance regression in :meth:`MultiIndex.equals` (:issue:`43549`)
• Fixed performance regression in :meth:`.DataFrameGroupBy.first`, :meth:`.SeriesGroupBy.first`, :meth:`.DataFrameGroupBy.last`, and :meth:`.SeriesGroupBy.last` with :class:`StringDtype` (:issue:`41596`)
• Fixed regression in :meth:`Series.cat.reorder_categories` failing to update the categories on the Series (:issue:`43232`)
• Fixed regression in :meth:`Series.cat.categories` setter failing to update the categories on the Series (:issue:`43334`)
• Fixed regression in :func:`read_csv` raising UnicodeDecodeError exception when memory_map=True (:issue:`43540`)
• Fixed regression in :meth:`DataFrame.explode` raising AssertionError when column is any scalar which is not a string (:issue:`43314`)
• Fixed regression in :meth:`Series.aggregate` attempting to pass args and kwargs multiple times to the user supplied func in certain cases (:issue:`43357`)
• Fixed regression when iterating over a :class:`DataFrame.groupby.rolling` object causing the resulting DataFrames to have an incorrect index if the input groupings were not sorted (:issue:`43386`)
• Fixed regression in :meth:`DataFrame.groupby.rolling.cov` and :meth:`DataFrame.groupby.rolling.corr` computing incorrect results if the input groupings were not sorted (:issue:`43386`)

Bug fixes

• Fixed bug in :meth:`pandas.DataFrame.groupby.rolling` and :class:`pandas.api.indexers.FixedForwardWindowIndexer` leading to segfaults and window endpoints being mixed across groups (:issue:`43267`)
• Fixed bug in :meth:`.DataFrameGroupBy.mean` and :meth:`.SeriesGroupBy.mean` with datetimelike values including NaT values returning incorrect results (:issue:`43132`)
• Fixed bug in :meth:`Series.aggregate` not passing the first args to the user supplied func in certain cases (:issue:`43357`)
• Fixed memory leaks in :meth:`Series.rolling.quantile` and :meth:`Series.rolling.median` (:issue:`43339`)

Other

• The minimum version of Cython needed to compile pandas is now 0.29.24 (:issue:`43729`)

Contributors

.. contributors:: v1.3.3..v1.3.4