v0.18.0.txt

.. _whatsnew_0180:

v0.18.0 (January ??, 2016)
--------------------------

This is a major release from 0.17.1 and includes a small number of API changes, several new features,
enhancements, and performance improvements along with a large number of bug fixes. We recommend that all
users upgrade to this version.

Highlights include:

Check the :ref:`API Changes <whatsnew_0180.api>` and :ref:`deprecations <whatsnew_0180.deprecations>` before updating.

.. contents:: What's new in v0.18.0
    :local:
    :backlinks: none

.. _whatsnew_0180.enhancements:

New features
~~~~~~~~~~~~







.. _whatsnew_0180.enhancements.other:

Other enhancements
^^^^^^^^^^^^^^^^^^

- Handle truncated floats in SAS xport files (:issue:`11713`)
- ``read_excel`` now supports s3 urls of the format ``s3://bucketname/filename`` (:issue:`11447`)

.. _whatsnew_0180.enhancements.rounding:

Datetimelike rounding
^^^^^^^^^^^^^^^^^^^^^

``DatetimeIndex``, ``Timestamp``, ``TimedeltaIndex``, ``Timedelta`` have gained the ``.round()`` method for datetimelike rounding. (:issue:`4314`)

Naive datetimes

.. ipython:: python

   dr = pd.date_range('20130101 09:12:56.1234', periods=3)
   dr
   dr.round('s')

   # Timestamp scalar
   dr[0]
   dr[0].round('10s')

Tz-aware are rounded in local times

.. ipython:: python

   dr = dr.tz_localize('US/Eastern')
   dr
   dr.round('s')

Timedeltas

.. ipython:: python

   t = timedelta_range('1 days 2 hr 13 min 45 us',periods=3,freq='d')
   t
   t.round('10min')

   # Timedelta scalar
   t[0]
   t[0].round('2h')


In addition, ``.round()`` will be available thru the ``.dt`` accessor of ``Series``.

.. ipython:: python

   s = Series(dr)
   s
   s.dt.round('D')

.. _whatsnew_0180.api:

.. _whatsnew_0180.api_breaking:

Backwards incompatible API changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Bug in QuarterBegin with n=0
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In previous versions, the behavior of the QuarterBegin offset was inconsistent
depending on the date when the ``n`` parameter was 0.

The general semantics of anchored offsets for ``n=0`` is to not move the date
when it is an anchor point (e.g., a quarter start date), and otherwise roll
forward to the next anchor point.

.. ipython:: python

   d = pd.Timestamp('2014-02-01')
   d
   d + pd.offsets.QuarterBegin(n=0, startingMonth=2)
   d + pd.offsets.QuarterBegin(n=0, startingMonth=1)

For the ``QuarterBegin`` offset in previous versions, the date would be rolled
*backwards* if date was in the same month as the quarter start date.

.. code-block:: python

   In [3]: d = pd.Timestamp('2014-02-15')

   In [4]: d + pd.offsets.QuarterBegin(n=0, startingMonth=2)
   Out[4]: Timestamp('2014-02-01 00:00:00')

This behavior has been corrected in version 0.18.0, which is consistent with
other anchored offsets like ``MonthBegin`` and ``YearBegin``.

.. ipython:: python

   d = pd.Timestamp('2014-02-15')
   d + pd.offsets.QuarterBegin(n=0, startingMonth=2)


Other API Changes
^^^^^^^^^^^^^^^^^












.. _whatsnew_0180.deprecations:

Deprecations
^^^^^^^^^^^^






.. _whatsnew_0180.prior_deprecations:

Removal of prior version deprecations/changes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^







.. _whatsnew_0180.performance:

Performance Improvements
~~~~~~~~~~~~~~~~~~~~~~~~

- Improved performance of ``andrews_curves`` (:issue:`11534`)









.. _whatsnew_0180.bug_fixes:

Bug Fixes
~~~~~~~~~

- Bug in ``GroupBy.size`` when data-frame is empty. (:issue:`11699`)














- Bug in ``Timedelta.round`` with negative values (:issue:`11690`)
- Bug in ``.loc`` against ``CategoricalIndex`` may result in normal ``Index`` (:issue:`11586`)






- Bug groupby on tz-aware data where selection not returning ``Timestamp`` (:issue:`11616`)






- Bug in timezone info lost when broadcasting scalar datetime to ``DataFrame`` (:issue:`11682`)








- Bug in ``.loc`` result with duplicated key may have ``Index`` with incorrect dtype (:issue:`11497`)
- Bug in ``pd.rolling_median`` where memory allocation failed even with sufficient memory (:issue:`11696`)

- Bug in ``df.replace`` while replacing value in mixed dtype ``Dataframe`` (:issue:`11698`)