What’s new in 1.2.2 (February 09, 2021)

These are the changes in pandas 1.2.2. See Release notes for a full changelog including other versions of pandas.

Fixed regressions

• Fixed regression in read_excel() that caused it to raise AttributeError when checking version of older xlrd versions (GH 38955)

• Fixed regression in DataFrame constructor reordering element when construction from datetime ndarray with dtype not "datetime64[ns]" (GH 39422)

• Fixed regression in DataFrame.astype() and Series.astype() not casting to bytes dtype (GH 39474)

• Fixed regression in to_pickle() failing to create bz2/xz compressed pickle files with protocol=5 (GH 39002)

• Fixed regression in pandas.testing.assert_series_equal() and pandas.testing.assert_frame_equal() always raising AssertionError when comparing extension dtypes (GH 39410)

• Fixed regression in to_csv() opening codecs.StreamWriter in binary mode instead of in text mode and ignoring user-provided mode (GH 39247)

• Fixed regression in Categorical.astype() casting to incorrect dtype when np.int32 is passed to dtype argument (GH 39402)

• Fixed regression in to_excel() creating corrupt files when appending (mode="a") to an existing file (GH 39576)

• Fixed regression in DataFrame.transform() failing in case of an empty DataFrame or Series (GH 39636)

• Fixed regression in groupby() or resample() when aggregating an all-NaN or numeric object dtype column (GH 39329)

• Fixed regression in Rolling.count() where the min_periods argument would be set to 0 after the operation (GH 39554)

• Fixed regression in read_excel() that incorrectly raised when the argument io was a non-path and non-buffer and the engine argument was specified (GH 39528)

Bug fixes

• pandas.read_excel() error message when a specified sheetname does not exist is now uniform across engines (GH 39250)

• Fixed bug in pandas.read_excel() producing incorrect results when the engine openpyxl is used and the excel file is missing or has incorrect dimension information; the fix requires openpyxl >= 3.0.0, prior versions may still fail (GH 38956, GH 39001)

• Fixed bug in pandas.read_excel() sometimes producing a DataFrame with trailing rows of np.nan when the engine openpyxl is used (GH 39181)

Contributors

For contributors, please see /usr/share/doc/contributors_list.txt or https://github.com/pandas-dev/pandas/graphs/contributors