v1.4.3.rst

What's new in 1.4.3 (June 23, 2022)

These are the changes in pandas 1.4.3. See :ref:`release` for a full changelog including other versions of pandas.

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Behavior of concat with empty or all-NA DataFrame columns

The behavior change in version 1.4.0 to stop ignoring the data type of empty or all-NA columns with float or object dtype in :func:`concat` (:ref:`whatsnew_140.notable_bug_fixes.concat_with_empty_or_all_na`) has been reverted (:issue:`45637`).

Fixed regressions

• Fixed regression in :meth:`DataFrame.replace` when the replacement value was explicitly None when passed in a dictionary to to_replace also casting other columns to object dtype even when there were no values to replace (:issue:`46634`)
• Fixed regression in :meth:`DataFrame.to_csv` raising error when :class:`DataFrame` contains extension dtype categorical column (:issue:`46297`, :issue:`46812`)
• Fixed regression in representation of dtypes attribute of :class:`MultiIndex` (:issue:`46900`)
• Fixed regression when setting values with :meth:`DataFrame.loc` updating :class:`RangeIndex` when index was set as new column and column was updated afterwards (:issue:`47128`)
• Fixed regression in :meth:`DataFrame.fillna` and :meth:`DataFrame.update` creating a copy when updating inplace (:issue:`47188`)
• Fixed regression in :meth:`DataFrame.nsmallest` led to wrong results when the sorting column has np.nan values (:issue:`46589`)
• Fixed regression in :func:`read_fwf` raising ValueError when widths was specified with usecols (:issue:`46580`)
• Fixed regression in :func:`concat` not sorting columns for mixed column names (:issue:`47127`)
• Fixed regression in :meth:`.Groupby.transform` and :meth:`.Groupby.agg` failing with engine="numba" when the index was a :class:`MultiIndex` (:issue:`46867`)
• Fixed regression in NaN comparison for :class:`Index` operations where the same object was compared (:issue:`47105`)
• Fixed regression is :meth:`.Styler.to_latex` and :meth:`.Styler.to_html` where buf failed in combination with encoding (:issue:`47053`)
• Fixed regression in :func:`read_csv` with index_col=False identifying first row as index names when header=None (:issue:`46955`)
• Fixed regression in :meth:`.DataFrameGroupBy.agg` when used with list-likes or dict-likes and axis=1 that would give incorrect results; now raises NotImplementedError (:issue:`46995`)
• Fixed regression in :meth:`DataFrame.resample` and :meth:`DataFrame.rolling` when used with list-likes or dict-likes and axis=1 that would raise an unintuitive error message; now raises NotImplementedError (:issue:`46904`)
• Fixed regression in :func:`testing.assert_index_equal` when check_order=False and :class:`Index` has extension or object dtype (:issue:`47207`)
• Fixed regression in :func:`read_excel` returning ints as floats on certain input sheets (:issue:`46988`)
• Fixed regression in :meth:`DataFrame.shift` when axis is columns and fill_value is absent, freq is ignored (:issue:`47039`)
• Fixed regression in :meth:`DataFrame.to_json` causing a segmentation violation when :class:`DataFrame` is created with an index parameter of the type :class:`PeriodIndex` (:issue:`46683`)

Bug fixes

• Bug in :func:`pandas.eval`, :meth:`DataFrame.eval` and :meth:`DataFrame.query` where passing empty local_dict or global_dict was treated as passing None (:issue:`47084`)
• Most I/O methods no longer suppress OSError and ValueError when closing file handles (:issue:`47136`)
• Improving error message raised by :meth:`DataFrame.from_dict` when passing an invalid orient parameter (:issue:`47450`)

Other

• The minimum version of Cython needed to compile pandas is now 0.29.30 (:issue:`41935`)

Contributors

.. contributors:: v1.4.2..v1.4.3