v0.10.0.txt

.. _whatsnew_0100:

v0.10.0 (December ??, 2012)
---------------------------

This is a major release from 0.9.1 and includes several new features and
enhancements along with a large number of bug fixes.

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

Updated PyTables Support
~~~~~~~~~~~~~~~~~~~~~~~~

:ref:`Docs <io-hdf5>` for PyTables ``Table`` format & several enhancements to the api. Here is a taste of what to expect.


    .. ipython:: python
       :suppress:
       :okexcept:

       os.remove('store.h5')

    .. ipython:: python

       store = HDFStore('store.h5')
       df = DataFrame(randn(8, 3), index=date_range('1/1/2000', periods=8),
                  columns=['A', 'B', 'C'])
       df

       # appending data frames
       df1 = df[0:4]
       df2 = df[4:]
       store.append('df', df1)
       store.append('df', df2)
       store

       # selecting the entire store
       store.select('df')

    .. ipython:: python

       from pandas.io.pytables import Term
       wp = Panel(randn(2, 5, 4), items=['Item1', 'Item2'],
              major_axis=date_range('1/1/2000', periods=5),
              minor_axis=['A', 'B', 'C', 'D'])
       wp

       # storing a panel
       store.append('wp',wp)

       # selecting via A QUERY
       store.select('wp',
         [ Term('major_axis>20000102'), Term('minor_axis', '=', ['A','B']) ])

       # removing data from tables
       store.remove('wp', [ 'major_axis', '>', wp.major_axis[3] ])
       store.select('wp')

       # deleting a store
       del store['df']
       store

  **Enhancements**

       - added mixed-dtype support!

          .. ipython:: python

             df['string'] = 'string'
	     df['int']    = 1

             store.append('df',df)
	     df1 = store.select('df')
	     df1
	     df1.get_dtype_counts()

       - performance improvments on table writing
       - support for arbitrarily indexed dimensions
	   - ``SparseSeries`` now has a ``density`` property (#2384)

  **Bug Fixes**

       - added ``Term`` method of specifying where conditions (GH1996_).
       - ``del store['df']`` now call ``store.remove('df')`` for store deletion
       - deleting of consecutive rows is much faster than before
       - ``min_itemsize`` parameter can be specified in table creation to force a minimum size for indexing columns
         (the previous implementation would set the column size based on the first append)
       - indexing support via ``create_table_index`` (requires PyTables >= 2.3) (GH698_).
       - appending on a store would fail if the table was not first created via ``put``
       - minor change to select and remove: require a table ONLY if where is also provided (and not None)

    .. ipython:: python
       :suppress:

       store.close()
       import os
       os.remove('store.h5')

API changes
~~~~~~~~~~~

  - ``Series.apply`` will now operate on a returned value from the applied function, that is itself a series, and possibly upcast the result to a DataFrame

    .. ipython:: python

        def f(x):
	        return Series([ x, x**2 ], index = ['x', 'x^s'])
        s = Series(np.random.rand(5))
	    s
        s.apply(f)

    This is conceptually similar to the following.

    .. ipython:: python

        concat([ f(y) for x, y in s.iteritems() ], axis=1).T

  - New API functions for working with pandas options (GH2097_):

    - ``get_option`` / ``set_option`` - get/set the value of an option. Partial names are accepted.
    - ``reset_option`` - reset one or more options to their default value. Partial names are accepted.
    - ``describe_option`` - print a description of one or more options. When called  with no arguments. print all registered options.

    Note: ``set_printoptions``/ ``reset_printoptions``  are now deprecated (but functioning), the print options now live under "print.XYZ". For example:


    .. ipython:: python

       import pandas as pd
       pd.get_option("print.max_rows")


  - to_string() methods now always return unicode strings  (GH2224_).


See the `full release notes
<https://github.com/pydata/pandas/blob/master/RELEASE.rst>`__ or issue tracker
on GitHub for a complete list.

.. _GH698: https://github.com/pydata/pandas/issues/698
.. _GH1996: https://github.com/pydata/pandas/issues/1996
.. _GH2316: https://github.com/pydata/pandas/issues/2316
.. _GH2097: https://github.com/pydata/pandas/issues/2097
.. _GH2224: https://github.com/pydata/pandas/issues/2224