v.0.5.0 (October 24, 2011)

New features

• Added DataFrame.align method with standard join options
• Added parse_dates option to read_csv and read_table methods to optionally try to parse dates in the index columns
• 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 (GH242)
• Added ability to join on multiple columns in DataFrame.join (GH214)
• Added private _get_duplicates function to Index for identifying duplicate values more easily (ENH5c)
• Added column attribute access to DataFrame.
• Added Python tab completion hook for DataFrame columns. (GH233, GH230)
• Implemented Series.describe for Series containing objects (GH241)
• Added inner join option to DataFrame.join when joining on key(s) (GH248)
• Implemented selecting DataFrame columns by passing a list to __getitem__ (GH253)
• Implemented & and | to intersect / union Index objects, respectively (GH261)
• Added pivot_table convenience function to pandas namespace (GH234)
• Implemented Panel.rename_axis function (GH243)
• DataFrame will show index level names in console output (GH334)
• Implemented Panel.take
• Added set_eng_float_format for alternate DataFrame floating point string formatting (ENH61)
• Added convenience set_index function for creating a DataFrame index from its existing columns
• Implemented groupby hierarchical index level name (GH223)
• Added support for different delimiters in DataFrame.to_csv (GH244)
• TODO: DOCS ABOUT TAKE METHODS

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 (GH211)
• VBENCH Improved speed of DataFrame.xs on mixed-type DataFrame objects by about 5x, regression from 0.3.0 (GH215)
• 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 (GH212)
• VBENCH Significantly speed up DataFrame __repr__ and count on large mixed-type DataFrame objects

Contributors

A total of 9 people contributed patches to this release. People with a “+” by their names contributed a patch for the first time.

• Aman Thakral +
• Luca Beltrame +
• Nick Pentreath +
• Skipper Seabold
• Thomas Kluyver +
• Wes McKinney
• Yaroslav Halchenko +
• lodagro +
• unknown +