What’s new in 1.1.1 (August 20, 2020)

These are the changes in pandas 1.1.1. See Release notes for a full changelog including other versions of pandas.

Fixed regressions

• Fixed regression in CategoricalIndex.format() where, when stringified scalars had different lengths, the shorter string would be right-filled with spaces, so it had the same length as the longest string (GH35439)

• Fixed regression in Series.truncate() when trying to truncate a single-element series (GH35544)

• Fixed regression where DataFrame.to_numpy() would raise a RuntimeError for mixed dtypes when converting to str (GH35455)

• Fixed regression where read_csv() would raise a ValueError when pandas.options.mode.use_inf_as_na was set to True (GH35493)

• Fixed regression where pandas.testing.assert_series_equal() would raise an error when non-numeric dtypes were passed with check_exact=True (GH35446)

• Fixed regression in .groupby(..).rolling(..) where column selection was ignored (GH35486)

• Fixed regression where DataFrame.interpolate() would raise a TypeError when the DataFrame was empty (GH35598)

• Fixed regression in DataFrame.shift() with axis=1 and heterogeneous dtypes (GH35488)

• Fixed regression in DataFrame.diff() with read-only data (GH35559)

• Fixed regression in .groupby(..).rolling(..) where a segfault would occur with center=True and an odd number of values (GH35552)

• Fixed regression in DataFrame.apply() where functions that altered the input in-place only operated on a single row (GH35462)

• Fixed regression in DataFrame.reset_index() would raise a ValueError on empty DataFrame with a MultiIndex with a datetime64 dtype level (GH35606, GH35657)

• Fixed regression where pandas.merge_asof() would raise a UnboundLocalError when left_index, right_index and tolerance were set (GH35558)

• Fixed regression in .groupby(..).rolling(..) where a custom BaseIndexer would be ignored (GH35557)

• Fixed regression in DataFrame.replace() and Series.replace() where compiled regular expressions would be ignored during replacement (GH35680)

• Fixed regression in aggregate() where a list of functions would produce the wrong results if at least one of the functions did not aggregate (GH35490)

• Fixed memory usage issue when instantiating large pandas.arrays.StringArray (GH35499)

Bug fixes

• Bug in Styler whereby cell_ids argument had no effect due to other recent changes (GH35588) (GH35663)

• Bug in pandas.testing.assert_series_equal() and pandas.testing.assert_frame_equal() where extension dtypes were not ignored when check_dtypes was set to False (GH35715)

• Bug in to_timedelta() fails when arg is a Series with Int64 dtype containing null values (GH35574)

• Bug in .groupby(..).rolling(..) where passing closed with column selection would raise a ValueError (GH35549)

• Bug in DataFrame constructor failing to raise ValueError in some cases when data and index have mismatched lengths (GH33437)

Contributors

A total of 20 people contributed patches to this release. People with a “+” by their names contributed a patch for the first time.

• Ali McMaster

• Daniel Saxton

• Eric Goddard +

• Fangchen Li

• Isaac Virshup

• Joris Van den Bossche

• Kevin Sheppard

• Matthew Roeschke

• MeeseeksMachine +

• Pandas Development Team

• Richard Shadrach

• Simon Hawkins

• Terji Petersen

• Tom Augspurger

• Yutaro Ikeda +

• attack68 +

• edwardkong +

• gabicca +

• jbrockmendel

• sanderland +

What’s new in 1.1.2 (September 8, 2020) What’s new in 1.1.0 (July 28, 2020)