joining/merging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386 14.3 Merging with Multi-indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 15 Reshaping Here – MultiIndexing Using Slicers, See Here. – Ability to join a singly-indexed DataFrame with a multi-indexed DataFrame, see Here – More consistency in groupby results and more flexible groupby specifications 14.0 (May 31 , 2014) 5 pandas: powerful Python data analysis toolkit, Release 0.14.0 In [11]: df_multi.set_index(tuple_ind) Out[11]: 0 1 (a, c) 0.471435 -1.190976 (a, d) 1.432707 -0.312652 (b, c) -0

joining/merging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472 17.3 Merging with Multi-indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481 18 Reshaping passing dtype and names and the parsed data is a different data type (GH8833) • Bug in slicing a multi-index with an empty list and at least one boolean indexer (GH8781) • io.data.Options now raises RemoteDataError • Bug in read_csv, dialect parameter would not take a string (:issue: 8703) • Bug in slicing a multi-index level with an empty-list (GH8737) • Bug in numeric index operations of add/sub with Float/Index

joining/merging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462 17.3 Merging with Multi-indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471 18 Reshaping • Bug in read_csv, dialect parameter would not take a string (:issue: 8703) • Bug in slicing a multi-index level with an empty-list (GH8737) • Bug in numeric index operations of add/sub with Float/Index What’s New pandas: powerful Python data analysis toolkit, Release 0.15.1 This can also be seen in multi-axis indexing with a Panel. In [86]: p = Panel(np.arange(2*3*4).reshape(2,3,4), ....: items=[’ItemA’

create a single DataFrame . . . . . . . . . . . . . . . . . 451 7.9.1.2 Parsing date components in multi-columns . . . . . . . . . . . . . . . . . . . . . . 451 7.9.1.3 Skip row between header and data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540 9.11.5 Sorting by a multi-index column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542 9.12 Copying . by factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 752 16.10.2 Multi-column factorization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 752 16

create a single DataFrame . . . . . . . . . . . . . . . . . 453 7.9.1.2 Parsing date components in multi-columns . . . . . . . . . . . . . . . . . . . . . . 453 7.9.1.3 Skip row between header and data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542 9.11.5 Sorting by a multi-index column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544 9.12 Copying . by factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 754 16.10.2 Multi-column factorization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755 16

threads to run simultaneously during computation, potentially allowing performance improvements from multi-threading. Notably groupby, nsmallest, value_counts and some indexing operations benefit from this GIL could benefit an application that uses threads for user interactions (e.g. QT), or performing multi-threaded computations. A nice example of a library that can handle these types of computation-in-parallel stack when index or columns are not unique. (GH10417) • Bug in setting a Panel when an axis has a multi-index (GH10360) • Bug in USFederalHolidayCalendar where USMemorialDay and USMartinLutherKingJr were

create a single DataFrame . . . . . . . . . . . . . . . . . 480 7.9.1.2 Parsing date components in multi-columns . . . . . . . . . . . . . . . . . . . . . . 481 7.9.1.3 Skip row between header and data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569 9.11.5 Sorting by a multi-index column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570 9.12 Copying . by factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 784 16.10.2 Multi-column factorization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 785 16

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482 10.11.5 Sorting by a multi-index column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484 10.12 Copying . . . . . 695 18.2.5 Joining a single Index to a Multi-index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697 18.2.6 Joining with two multi-indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804 22.4.2 Multi Column Sorting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805 22

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484 10.11.5 Sorting by a multi-index column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486 10.12 Copying . . . . . 697 18.2.5 Joining a single Index to a Multi-index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 699 18.2.6 Joining with two multi-indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806 22.4.2 Multi Column Sorting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807 22

of bug fixes. Highlites include a consistent I/O API naming scheme, routines to read html, write multi-indexes to csv files, read & write STATA data files, read & write JSON format files, Python 3 support additions in order to support more explicit location based indexing. Pandas now supports three types of multi-axis indexing. • .loc is strictly label based, will raise KeyError when the items are not found, 085360 -0.334353 2000-01-07 1.169735 -0.878264 2000-01-08 -0.181581 1.156482 HDFStore now serializes multi-index dataframes when appending tables. In [21]: index = MultiIndex(levels=[[’foo’, ’bar’, ’baz’