v1.6.0.rst

What's new in 1.6.0 (??)

These are the changes in pandas 1.6.0. See :ref:`release` for a full changelog including other versions of pandas.

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Enhancements

enhancement1

enhancement2

Other enhancements

• :meth:`Series.add_suffix`, :meth:`DataFrame.add_suffix`, :meth:`Series.add_prefix` and :meth:`DataFrame.add_prefix` support an axis argument. If axis is set, the default behaviour of which axis to consider can be overwritten (:issue:`47819`)

Notable bug fixes

These are bug fixes that might have notable behavior changes.

Using DataFrame.at to expand DataFrame

:meth:`DataFrame.at` would allow the addition of columns and rows to a DataFrame. (:issue:`48323`)

In [3]: frame = pd.DataFrame({"a": [1, 2]})
In [4]: frame
Out[4]:
   a
0  1
1  2

Old Behavior

In [5]: frame.at[2, "a"] = 7
In [6]: frame
Out[6]:
   a
0  1
1  2
2  7

New Behavior

In [5]: frame.at[2, "a"] = 7
Out[5]:
KeyError: 2

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

Deprecations

Performance improvements

• Performance improvement in :meth:`.GroupBy.median` for nullable dtypes (:issue:`37493`)
• Performance improvement in :meth:`MultiIndex.argsort` and :meth:`MultiIndex.sort_values` (:issue:`48406`)
• Performance improvement in :meth:`.GroupBy.mean` and :meth:`.GroupBy.var` for extension array dtypes (:issue:`37493`)
• Performance improvement for :meth:`Series.value_counts` with nullable dtype (:issue:`48338`)
• Performance improvement for :class:`Series` constructor passing integer numpy array with nullable dtype (:issue:`48338`)
• Performance improvement for :meth:`MultiIndex.unique` (:issue:`48335`)

Bug fixes

Categorical

Datetimelike

Timedelta

Timezones

Numeric

Conversion

Strings

Interval

Indexing

• Bug in :meth:`DataFrame.reindex` filling with wrong values when indexing columns and index for uint dtypes (:issue:`48184`)
• Bug in :meth:`DataFrame.reindex` casting dtype to object when :class:`DataFrame` has single extension array column when re-indexing columns and index (:issue:`48190`)
• Bug in :func:`~DataFrame.describe` when formatting percentiles in the resulting index showed more decimals than needed (:issue:`46362`)

Missing

MultiIndex

• Bug in :meth:`MultiIndex.unique` losing extension array dtype (:issue:`48335`)
• Bug in :meth:`MultiIndex.append` not checking names for equality (:issue:`48288`)

I/O

Period

• Bug in :meth:`Period.strftime` and :meth:`PeriodIndex.strftime`, raising UnicodeDecodeError when a locale-specific directive was passed (:issue:`46319`)

Plotting

Groupby/resample/rolling

Reshaping

• Bug in :func:`join` when left_on or right_on is or includes a :class:`CategoricalIndex` incorrectly raising AttributeError (:issue:`48464`)

Sparse

ExtensionArray

• Bug in :meth:`Series.mean` overflowing unnecessarily with nullable integers (:issue:`48378`)

Styler

Other

Contributors