.. _whatsnew_0801:

v0.8.1 (July 22, 2012)
----------------------

This release includes a few new features, performance enhancements, and over 30
bug fixes from 0.8.0.  New features include notably NA friendly string
processing functionality and a series of new plot types and options.

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

  - Add :ref:`vectorized string processing methods <text.string_methods>`
    accessible via Series.str (:issue:`620`)
  - Add option to disable adjustment in EWMA (:issue:`1584`)
  - :ref:`Radviz plot <visualization.radviz>` (:issue:`1566`)
  - :ref:`Parallel coordinates plot <visualization.parallel_coordinates>`
  - :ref:`Bootstrap plot <visualization.bootstrap>`
  - Per column styles and secondary y-axis plotting (:issue:`1559`)
  - New datetime converters millisecond plotting  (:issue:`1599`)
  - Add option to disable "sparse" display of hierarchical indexes (:issue:`1538`)
  - Series/DataFrame's ``set_index`` method can :ref:`append levels
    <indexing.set_index>` to an existing Index/MultiIndex (:issue:`1569`, :issue:`1577`)

Performance improvements
~~~~~~~~~~~~~~~~~~~~~~~~

  - Improved implementation of rolling min and max (thanks to `Bottleneck
    <http://berkeleyanalytics.com/bottleneck/>`__ !)
  - Add accelerated ``'median'`` GroupBy option (:issue:`1358`)
  - Significantly improve the performance of parsing ISO8601-format date
    strings with ``DatetimeIndex`` or ``to_datetime`` (:issue:`1571`)
  - Improve the performance of GroupBy on single-key aggregations and use with
    Categorical types
  - Significant datetime parsing performance improvements

