Skip to main content
`Ctrl`+`K`

# What’s new in 1.4.3 (June 23, 2022)

These are the changes in pandas 1.4.3. See Release notes for a full changelog including other versions of pandas.

## 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 `concat()` (Ignoring dtypes in concat with empty or all-NA columns) has been reverted (GH 45637).

## Fixed regressions

- Fixed regression in `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 (GH 46634)

- Fixed regression in `DataFrame.to_csv()` raising error when `DataFrame` contains extension dtype categorical column (GH 46297, GH 46812)

- Fixed regression in representation of `dtypes` attribute of `MultiIndex` (GH 46900)

- Fixed regression when setting values with `DataFrame.loc()` updating `RangeIndex` when index was set as new column and column was updated afterwards (GH 47128)

- Fixed regression in `DataFrame.fillna()` and `DataFrame.update()` creating a copy when updating inplace (GH 47188)

- Fixed regression in `DataFrame.nsmallest()` led to wrong results when the sorting column has `np.nan` values (GH 46589)

- Fixed regression in `read_fwf()` raising `ValueError` when `widths` was specified with `usecols` (GH 46580)

- Fixed regression in `concat()` not sorting columns for mixed column names (GH 47127)

- Fixed regression in `Groupby.transform()` and `Groupby.agg()` failing with `engine="numba"` when the index was a `MultiIndex` (GH 46867)

- Fixed regression in `NaN` comparison for `Index` operations where the same object was compared (GH 47105)

- Fixed regression is `Styler.to_latex()` and `Styler.to_html()` where `buf` failed in combination with `encoding` (GH 47053)

- Fixed regression in `read_csv()` with `index_col=False` identifying first row as index names when `header=None` (GH 46955)

- Fixed regression in `DataFrameGroupBy.agg()` when used with list-likes or dict-likes and `axis=1` that would give incorrect results; now raises `NotImplementedError` (GH 46995)

- Fixed regression in `DataFrame.resample()` and `DataFrame.rolling()` when used with list-likes or dict-likes and `axis=1` that would raise an unintuitive error message; now raises `NotImplementedError` (GH 46904)

- Fixed regression in `testing.assert_index_equal()` when `check_order=False` and `Index` has extension or object dtype (GH 47207)

- Fixed regression in `read_excel()` returning ints as floats on certain input sheets (GH 46988)

- Fixed regression in `DataFrame.shift()` when `axis` is `columns` and `fill_value` is absent, `freq` is ignored (GH 47039)

- Fixed regression in `DataFrame.to_json()` causing a segmentation violation when `DataFrame` is created with an `index` parameter of the type `PeriodIndex` (GH 46683)

## Bug fixes

- Bug in `pandas.eval()`, `DataFrame.eval()` and `DataFrame.query()` where passing empty `local_dict` or `global_dict` was treated as passing `None` (GH 47084)

- Most I/O methods no longer suppress `OSError` and `ValueError` when closing file handles (GH 47136)

- Improving error message raised by `DataFrame.from_dict()` when passing an invalid `orient` parameter (GH 47450)

## Other

- The minimum version of Cython needed to compile pandas is now `0.29.30` (GH 41935)

## Contributors

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