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)

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


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 +
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