.. _whatsnew_050: Version 0.5.0 (October 24, 2011) -------------------------------- {{ header }} New features ~~~~~~~~~~~~ - :ref:`Added ` ``DataFrame.align`` method with standard join options - :ref:`Added ` ``parse_dates`` option to ``read_csv`` and ``read_table`` methods to optionally try to parse dates in the index columns - :ref:`Added ` ``nrows``, ``chunksize``, and ``iterator`` arguments to ``read_csv`` and ``read_table``. The last two return a new ``TextParser`` class capable of lazily iterating through chunks of a flat file (:issue:`242`) - :ref:`Added ` ability to join on multiple columns in ``DataFrame.join`` (:issue:`214`) - Added private ``_get_duplicates`` function to ``Index`` for identifying duplicate values more easily (ENH5c_) - :ref:`Added ` column attribute access to DataFrame. - :ref:`Added ` Python tab completion hook for DataFrame columns. (:issue:`233`, :issue:`230`) - :ref:`Implemented ` ``Series.describe`` for Series containing objects (:issue:`241`) - :ref:`Added ` inner join option to ``DataFrame.join`` when joining on key(s) (:issue:`248`) - :ref:`Implemented ` selecting DataFrame columns by passing a list to ``__getitem__`` (:issue:`253`) - :ref:`Implemented ` & and | to intersect / union Index objects, respectively (:issue:`261`) - :ref:`Added` ``pivot_table`` convenience function to pandas namespace (:issue:`234`) - :ref:`Implemented ` ``Panel.rename_axis`` function (:issue:`243`) - DataFrame will show index level names in console output (:issue:`334`) - :ref:`Implemented ` ``Panel.take`` - :ref:`Added` ``set_eng_float_format`` for alternate DataFrame floating point string formatting (ENH61_) - :ref:`Added ` convenience ``set_index`` function for creating a DataFrame index from its existing columns - :ref:`Implemented ` ``groupby`` hierarchical index level name (:issue:`223`) - :ref:`Added ` support for different delimiters in ``DataFrame.to_csv`` (:issue:`244`) Performance enhancements ~~~~~~~~~~~~~~~~~~~~~~~~ - VBENCH Major performance improvements in file parsing functions ``read_csv`` and ``read_table`` - VBENCH Added Cython function for converting tuples to ndarray very fast. Speeds up many MultiIndex-related operations - VBENCH Refactored merging / joining code into a tidy class and disabled unnecessary computations in the float/object case, thus getting about 10% better performance (:issue:`211`) - VBENCH Improved speed of ``DataFrame.xs`` on mixed-type DataFrame objects by about 5x, regression from 0.3.0 (:issue:`215`) - VBENCH With new ``DataFrame.align`` method, speeding up binary operations between differently-indexed DataFrame objects by 10-25%. - VBENCH Significantly sped up conversion of nested dict into DataFrame (:issue:`212`) - VBENCH Significantly speed up DataFrame ``__repr__`` and ``count`` on large mixed-type DataFrame objects .. _ENH61: https://github.com/pandas-dev/pandas/commit/6141961 .. _ENH5c: https://github.com/pandas-dev/pandas/commit/5ca6ff5d822ee4ddef1ec0d87b6d83d8b4bbd3eb .. _whatsnew_0.5.0.contributors: Contributors ~~~~~~~~~~~~ .. contributors:: v0.4.0..v0.5.0