1.. _whatsnew_04x:
2
3Versions 0.4.1 through 0.4.3 (September 25 - October 9, 2011)
4-------------------------------------------------------------
5
6{{ header }}
7
8New features
9~~~~~~~~~~~~
10
11- Added Python 3 support using 2to3 (:issue:`200`)
12- :ref:`Added <dsintro.name_attribute>` ``name`` attribute to ``Series``, now
13  prints as part of ``Series.__repr__``
14- :ref:`Added <missing.isna>` instance methods ``isnull`` and ``notnull`` to
15  Series (:issue:`209`, :issue:`203`)
16- :ref:`Added <basics.align>` ``Series.align`` method for aligning two series
17  with choice of join method (ENH56_)
18- :ref:`Added <advanced.get_level_values>` method ``get_level_values`` to
19  ``MultiIndex`` (:issue:`188`)
20- Set values in mixed-type ``DataFrame`` objects via ``.ix`` indexing attribute (:issue:`135`)
21- Added new ``DataFrame`` :ref:`methods <basics.dtypes>`
22  ``get_dtype_counts`` and property ``dtypes`` (ENHdc_)
23- Added :ref:`ignore_index <merging.ignore_index>` option to
24  ``DataFrame.append`` to stack DataFrames (ENH1b_)
25- ``read_csv`` tries to :ref:`sniff <io.sniff>` delimiters using
26  ``csv.Sniffer`` (:issue:`146`)
27- ``read_csv`` can :ref:`read <io.csv_multiindex>` multiple columns into a
28  ``MultiIndex``; DataFrame's ``to_csv`` method writes out a corresponding
29  ``MultiIndex`` (:issue:`151`)
30- ``DataFrame.rename`` has a new ``copy`` parameter to :ref:`rename
31  <basics.rename>` a DataFrame in place (ENHed_)
32- :ref:`Enable <reshaping.unstack_by_name>` unstacking by name (:issue:`142`)
33- :ref:`Enable <advanced.sortlevel_byname>` ``sortlevel`` to work by level (:issue:`141`)
34
35Performance enhancements
36~~~~~~~~~~~~~~~~~~~~~~~~
37
38- Altered binary operations on differently-indexed SparseSeries objects
39  to use the integer-based (dense) alignment logic which is faster with a
40  larger number of blocks (:issue:`205`)
41- Wrote faster Cython data alignment / merging routines resulting in
42  substantial speed increases
43- Improved performance of ``isnull`` and ``notnull``, a regression from v0.3.0
44  (:issue:`187`)
45- Refactored code related to ``DataFrame.join`` so that intermediate aligned
46  copies of the data in each ``DataFrame`` argument do not need to be created.
47  Substantial performance increases result (:issue:`176`)
48- Substantially improved performance of generic ``Index.intersection`` and
49  ``Index.union``
50- Implemented ``BlockManager.take`` resulting in significantly faster ``take``
51  performance on mixed-type ``DataFrame`` objects (:issue:`104`)
52- Improved performance of ``Series.sort_index``
53- Significant groupby performance enhancement: removed unnecessary integrity
54  checks in DataFrame internals that were slowing down slicing operations to
55  retrieve groups
56- Optimized ``_ensure_index`` function resulting in performance savings in
57  type-checking Index objects
58- Wrote fast time series merging / joining methods in Cython. Will be
59  integrated later into DataFrame.join and related functions
60
61.. _ENH1b: https://github.com/pandas-dev/pandas/commit/1ba56251f0013ff7cd8834e9486cef2b10098371
62.. _ENHdc: https://github.com/pandas-dev/pandas/commit/dca3c5c5a6a3769ee01465baca04cfdfa66a4f76
63.. _ENHed: https://github.com/pandas-dev/pandas/commit/edd9f1945fc010a57fa0ae3b3444d1fffe592591
64.. _ENH56: https://github.com/pandas-dev/pandas/commit/56e0c9ffafac79ce262b55a6a13e1b10a88fbe93
65
66Contributors
67~~~~~~~~~~~~
68
69.. contributors:: v0.4.1..v0.4.3
70