.. _whatsnew_061:

v.0.6.1 (December 13, 2011)
---------------------------

New features
~~~~~~~~~~~~
- Can :ref:`append single rows <merging.append.row>` (as Series) to a DataFrame
- Add Spearman and Kendall rank :ref:`correlation <computation.correlation>`
  options to Series.corr and DataFrame.corr (:issue:`428`)
- :ref:`Added <indexing.basics.get_value>` ``get_value`` and ``set_value`` methods to
  Series, DataFrame, and Panel for very low-overhead access (>2x faster in many
  cases) to scalar elements (:issue:`437`, :issue:`438`). ``set_value`` is capable of
  producing an enlarged object.
- Add PyQt table widget to sandbox (:issue:`435`)
- DataFrame.align can :ref:`accept Series arguments <basics.align.frame.series>`
  and an :ref:`axis option <basics.df_join>` (:issue:`461`)
- Implement new :ref:`SparseArray <sparse.array>` and :ref:`SparseList <sparse.list>`
  data structures. SparseSeries now derives from SparseArray (:issue:`463`)
- :ref:`Better console printing options <basics.console_output>` (:issue:`453`)
- Implement fast :ref:`data ranking <computation.ranking>` for Series and
  DataFrame, fast versions of scipy.stats.rankdata (:issue:`428`)
- Implement :ref:`DataFrame.from_items <basics.dataframe.from_items>` alternate
  constructor (:issue:`444`)
- DataFrame.convert_objects method for :ref:`inferring better dtypes <basics.cast>`
  for object columns (:issue:`302`)
- Add :ref:`rolling_corr_pairwise <stats.moments.corr_pairwise>` function for
  computing Panel of correlation matrices (:issue:`189`)
- Add :ref:`margins <reshaping.pivot.margins>` option to :ref:`pivot_table
  <reshaping.pivot>` for computing subgroup aggregates (:issue:`114`)
- Add ``Series.from_csv`` function (:issue:`482`)
- :ref:`Can pass <stats.moments.binary>` DataFrame/DataFrame and
  DataFrame/Series to rolling_corr/rolling_cov (GH #462)
- MultiIndex.get_level_values can :ref:`accept the level name <advanced.get_level_values>`

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

- Improve memory usage of `DataFrame.describe` (do not copy data
  unnecessarily) (PR #425)

- Optimize scalar value lookups in the general case by 25% or more in Series
  and DataFrame

- Fix performance regression in cross-sectional count in DataFrame, affecting
  DataFrame.dropna speed
- Column deletion in DataFrame copies no data (computes views on blocks) (GH
  #158)