v1.4.1.rst

What's new in 1.4.1 (February ??, 2022)

These are the changes in pandas 1.4.1. See :ref:`release` for a full changelog including other versions of pandas.

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Fixed regressions

• Regression in :meth:`Series.mask` with inplace=True and PeriodDtype and an incompatible other coercing to a common dtype instead of raising (:issue:`45546`)
• Regression in :func:`.assert_frame_equal` not respecting check_flags=False (:issue:`45554`)
• Regression in :meth:`DataFrame.loc` raising ValueError when indexing (getting values) on a :class:`MultiIndex` with one level (:issue:`45779`)
• Regression in :meth:`Series.fillna` with downcast=False incorrectly downcasting object dtype (:issue:`45603`)
• Regression in :func:`api.types.is_bool_dtype` raising an AttributeError when evaluating a categorical :class:`Series` (:issue:`45615`)
• Regression in :meth:`DataFrame.iat` setting values leading to not propagating correctly in subsequent lookups (:issue:`45684`)
• Regression when setting values with :meth:`DataFrame.loc` losing :class:`Index` name if :class:`DataFrame` was empty before (:issue:`45621`)
• Regression in :meth:`~Index.join` with overlapping :class:`IntervalIndex` raising an InvalidIndexError (:issue:`45661`)
• Regression when setting values with :meth:`Series.loc` raising with all False indexer and :class:`Series` on the right hand side (:issue:`45778`)
• Regression in :func:`read_sql` with a DBAPI2 connection that is not an instance of sqlite3.Connection incorrectly requiring SQLAlchemy be installed (:issue:`45660`)
• Regression in :class:`DateOffset` when constructing with an integer argument with no keywords (e.g. pd.DateOffset(n)) would behave like datetime.timedelta(days=0) (:issue:`45643`, :issue:`45890`)

Bug fixes

• Fixed segfault in :meth:`DataFrame.to_json` when dumping tz-aware datetimes in Python 3.10 (:issue:`42130`)
• Stopped emitting unnecessary FutureWarning in :meth:`DataFrame.sort_values` with sparse columns (:issue:`45618`)
• Fixed window aggregations in :meth:`DataFrame.rolling` and :meth:`Series.rolling` to skip over unused elements (:issue:`45647`)
• Fixed builtin highlighters in :class:`.Styler` to be responsive to NA with nullable dtypes (:issue:`45804`)

Other

• Reverted performance speedup of :meth:`DataFrame.corr` for method=pearson to fix precision regression (:issue:`45640`, :issue:`42761`)

Contributors

.. contributors:: v1.4.0..v1.4.1|HEAD