v1.0.0.rst

What's new in 1.0.0 (??)

Warning

Starting with the 0.25.x series of releases, pandas only supports Python 3.5.3 and higher. See Dropping Python 2.7 for more details.

Warning

The minimum supported Python version will be bumped to 3.6 in a future release.

{{ header }}

These are the changes in pandas 1.0.0. See :ref:`release` for a full changelog including other versions of pandas.

Enhancements

Other enhancements

Backwards incompatible API changes

• :class:`pandas.core.groupby.GroupBy.transform` now raises on invalid operation names (:issue:`27489`).

Assignment to multiple columns of a DataFrame when some columns do not exist

Assignment to multiple columns of a :class:`DataFrame` when some of the columns do not exist would previously assign the values to the last column. Now, new columns would be constructed withe the right values. (:issue:`13658`)

.. ipython:: python

   df = pd.DataFrame({'a': [0, 1, 2], 'b': [3, 4, 5]})
   df

Previous behavior:

In [3]: df[['a', 'c']] = 1
In [4]: df
Out[4]:
   a  b
0  1  1
1  1  1
2  1  1

New behavior:

.. ipython:: python

   df[['a', 'c']] = 1
   df

Other API changes

• :meth:`pandas.api.types.infer_dtype` will now return "integer-na" for integer and np.nan mix (:issue:`27283`)

Deprecations

Removal of prior version deprecations/changes

• Removed the previously deprecated :meth:`Series.get_value`, :meth:`Series.set_value`, :meth:`DataFrame.get_value`, :meth:`DataFrame.set_value` (:issue:`17739`)
• Changed the the default value of inplace in :meth:`DataFrame.set_index` and :meth:`Series.set_axis`. It now defaults to False (:issue:`27600`)
• :meth:`pandas.Series.str.cat` now defaults to aligning others, using join='left' (:issue:`27611`)
• :meth:`pandas.Series.str.cat` does not accept list-likes within list-likes anymore (:issue:`27611`)
• Removed the previously deprecated :meth:`ExtensionArray._formatting_values`. Use :attr:`ExtensionArray._formatter` instead. (:issue:`23601`)
• Removed the previously deprecated IntervalIndex.from_intervals in favor of the :class:`IntervalIndex` constructor (:issue:`19263`)

Performance improvements

• Performance improvement in indexing with a non-unique :class:`IntervalIndex` (:issue:`27489`)
• Performance improvement in MultiIndex.is_monotonic (:issue:`27495`)
• Performance improvement in :func:`cut` when bins is an :class:`IntervalIndex` (:issue:`27668`)

Bug fixes

Categorical

• Added test to assert the :func:`fillna` raises the correct ValueError message when the value isn't a value from categories (:issue:`13628`)

Datetimelike

• Bug in :meth:`Series.__setitem__` incorrectly casting np.timedelta64("NaT") to np.datetime64("NaT") when inserting into a :class:`Series` with datetime64 dtype (:issue:`27311`)
• Bug in :meth:`Series.dt` property lookups when the underlying data is read-only (:issue:`27529`)

Timedelta

Timezones

Numeric

• Bug in :meth:`DataFrame.quantile` with zero-column :class:`DataFrame` incorrectly raising (:issue:`23925`)

Conversion

Strings

Interval

Indexing

Missing

MultiIndex

I/O

Plotting

• Bug in :meth:`Series.plot` not able to plot boolean values (:issue:`23719`)
• Bug in :meth:`DataFrame.plot` producing incorrect legend markers when plotting multiple series on the same axis (:issue:`18222`)
• Bug in :meth:`DataFrame.plot` when kind='box' and data contains datetime or timedelta data. These types are now automatically dropped (:issue:`22799`)

Groupby/resample/rolling

• Bug in :meth:`DataFrame.groupby` not offering selection by column name when axis=1 (:issue:`27614`)

Reshaping

Sparse

Build Changes

• Fixed pyqt development dependency issue because of different pyqt package name in conda and PyPI (:issue:`26838`)

ExtensionArray

Other

• Trying to set the display.precision, display.max_rows or display.max_columns using :meth:`set_option` to anything but a None or a positive int will raise a ValueError (:issue:`23348`)

Contributors