v2.1.0.rst

What's new in 2.1.0 (Month XX, 2023)

These are the changes in pandas 2.1.0. See :ref:`release` for a full changelog including other versions of pandas.

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Enhancements

enhancement1

enhancement2

Other enhancements

• :meth:`MultiIndex.sort_values` now supports na_position (:issue:`51612`)
• :meth:`MultiIndex.sortlevel` and :meth:`Index.sortlevel` gained a new keyword na_position (:issue:`51612`)
• Improve error message when setting :class:`DataFrame` with wrong number of columns through :meth:`DataFrame.isetitem` (:issue:`51701`)
• Let :meth:`DataFrame.to_feather` accept a non-default :class:`Index` and non-string column names (:issue:`51787`)
• :class:`api.extensions.ExtensionArray` now has a :meth:`~api.extensions.ExtensionArray.map` method (:issue:`51809`).

Notable bug fixes

These are bug fixes that might have notable behavior changes.

notable_bug_fix1

notable_bug_fix2

Backwards incompatible API changes

Increased minimum versions for dependencies

Some minimum supported versions of dependencies were updated. If installed, we now require:

Package	Minimum Version	Required	Changed
		X	X

For optional libraries the general recommendation is to use the latest version. The following table lists the lowest version per library that is currently being tested throughout the development of pandas. Optional libraries below the lowest tested version may still work, but are not considered supported.

Package	Minimum Version	Changed
		X

See :ref:`install.dependencies` and :ref:`install.optional_dependencies` for more.

Other API changes

• :class:`~arrays.ArrowExtensionArray` comparison methods now return data with :class:`ArrowDtype` with pyarrow.bool_ type instead of "boolean" dtype (:issue:`51643`)

Deprecations

• Deprecated silently dropping unrecognized timezones when parsing strings to datetimes (:issue:`18702`)
• Deprecating pinning group.name to each group in :meth:`SeriesGroupBy.aggregate` aggregations; if your operation requires utilizing the groupby keys, iterate over the groupby object instead (:issue:`41090`)
• Deprecated axis=1 in :meth:`DataFrame.groupby` and in :class:`Grouper` constructor, do frame.T.groupby(...) instead (:issue:`51203`)
• Deprecated passing a :class:`DataFrame` to :meth:`DataFrame.from_records`, use :meth:`DataFrame.set_index` or :meth:`DataFrame.drop` instead (:issue:`51353`)
• Deprecated accepting slices in :meth:`DataFrame.take`, call obj[slicer] or pass a sequence of integers instead (:issue:`51539`)

Performance improvements

• Performance improvement in :func:`read_parquet` on string columns when using use_nullable_dtypes=True (:issue:`47345`)
• Performance improvement in :meth:`DataFrame.clip` and :meth:`Series.clip` (:issue:`51472`)
• Performance improvement in :meth:`DataFrame.first_valid_index` and :meth:`DataFrame.last_valid_index` for extension array dtypes (:issue:`51549`)
• Performance improvement in :meth:`DataFrame.where` when cond is backed by an extension dtype (:issue:`51574`)
• Performance improvement in :meth:`read_orc` when reading a remote URI file path. (:issue:`51609`)
• Performance improvement in :meth:`MultiIndex.sortlevel` when ascending is a list (:issue:`51612`)
• Performance improvement in :meth:`~arrays.ArrowExtensionArray.isna` when array has zero nulls or is all nulls (:issue:`51630`)
• Performance improvement when parsing strings to boolean[pyarrow] dtype (:issue:`51730`)
• Performance improvement when searching an :class:`Index` sliced from other indexes (:issue:`51738`)
• Performance improvement in :meth:`Series.combine_first` (:issue:`51777`)

Bug fixes

Categorical

Datetimelike

• Bug in :meth:`Timestamp.round` with values close to the implementation bounds returning incorrect results instead of raising OutOfBoundsDatetime (:issue:`51494`)

Timedelta

• Bug in :meth:`Timedelta.round` with values close to the implementation bounds returning incorrect results instead of raising OutOfBoundsTimedelta (:issue:`51494`)
• Bug in :class:`TimedeltaIndex` division or multiplication leading to .freq of "0 Days" instead of None (:issue:`51575`)

Timezones

Numeric

• Bug in :meth:`Series.corr` and :meth:`Series.cov` raising AttributeError for masked dtypes (:issue:`51422`)

Conversion

• Bug in :meth:`ArrowDtype.numpy_dtype` returning nanosecond units for non-nanosecond pyarrow.timestamp and pyarrow.duration types (:issue:`51800`)

Strings

Interval

Indexing

Missing

MultiIndex

I/O

Period

• Bug in :class:`PeriodDtype` constructor failing to raise TypeError when no argument is passed or when None is passed (:issue:`27388`)
• Bug in :class:`PeriodDtype` constructor raising ValueError instead of TypeError when an invalid type is passed (:issue:`51790`)

Plotting

Groupby/resample/rolling

• Bug in :meth:`DataFrameGroupBy.idxmin`, :meth:`SeriesGroupBy.idxmin`, :meth:`DataFrameGroupBy.idxmax`, :meth:`SeriesGroupBy.idxmax` return wrong dtype when used on empty DataFrameGroupBy or SeriesGroupBy (:issue:`51423`)
• Bug in weighted rolling aggregations when specifying min_periods=0 (:issue:`51449`)
• Bug in :meth:`DataFrame.resample` and :meth:`Series.resample` in incorrectly allowing non-fixed freq when resampling on a :class:`TimedeltaIndex` (:issue:`51896`)

Reshaping

• Bug in :meth:`DataFrame.stack` losing extension dtypes when columns is a :class:`MultiIndex` and frame contains mixed dtypes (:issue:`45740`)
• Bug in :meth:`DataFrame.transpose` inferring dtype for object column (:issue:`51546`)
• Bug in :meth:`Series.combine_first` converting int64 dtype to float64 and losing precision on very large integers (:issue:`51764`)

Sparse

ExtensionArray

• Bug in :meth:`Series.any` and :meth:`Series.all` returning NA for empty or all null pyarrow-backed data when skipna=True (:issue:`51624`)

Styler

Other

Contributors