GH3876, GH3867, GH1305) • MultiIndex column support for reading and writing csv format files – The header option in read_csv now accepts a list of the rows from which to read the index. – The option, tupleize_cols R2C2 R_l0_g3,R_l1_g3,R3C0,R3C1,R3C2 R_l0_g4,R_l1_g4,R4C0,R4C1,R4C2 In [24]: pd.read_csv(’mi.csv’,header=[0,1,2,3],index_col=[0,1],tupleize_cols=False) C0 C_l0_g0 C_l0_g1 C_l0_g2 1.1. v0.12.0 (July 24 parts of the computation and is often unnec- essary. • The default column names for a file with no header have been changed to the integers 0 through N - 1. This is to create consistency with the DataFrame

v0.12.0 (July 24, 2013) 37 pandas: powerful Python data analysis toolkit, Release 0.13.1 – The header option in read_csv now accepts a list of the rows from which to read the index. – The option, tupleize_cols R2C2 R_l0_g3,R_l1_g3,R3C0,R3C1,R3C2 R_l0_g4,R_l1_g4,R4C0,R4C1,R4C2 In [24]: pd.read_csv(’mi.csv’,header=[0,1,2,3],index_col=[0,1],tupleize_cols=False) Out[24]: C0 C_l0_g0 C_l0_g1 C_l0_g2 C1 C_l1_g0 C_l1_g1 parts of the computation and is often unnec- essary. • The default column names for a file with no header have been changed to the integers 0 through N - 1. This is to create consistency with the DataFrame

values needed interpolating (GH7173). • Bug where col_space was ignored in DataFrame.to_string() when header=False (GH8230). • Bug with DatetimeIndex.asof incorrectly matching partial strings and returning values needed interpolating (GH7173). • Bug where col_space was ignored in DataFrame.to_string() when header=False (GH8230). • Bug in to_clipboard that would clip long column data (GH8305) • Bug in DataFrame dataframe to HTML it used to return Empty DataFrame. This special case has been removed, instead a header with the column names is returned (GH6062). • Series and Index now internall share more common operations

values needed interpolating (GH7173). • Bug where col_space was ignored in DataFrame.to_string() when header=False (GH8230). • Bug with DatetimeIndex.asof incorrectly matching partial strings and returning values needed interpolating (GH7173). • Bug where col_space was ignored in DataFrame.to_string() when header=False (GH8230). • Bug in to_clipboard that would clip long column data (GH8305) • Bug in DataFrame dataframe to HTML it used to return Empty DataFrame. This special case has been removed, instead a header with the column names is returned (GH6062). • Series and Index now internall share more common operations

dataframe to HTML it used to return Empty DataFrame. This special case has been removed, instead a header with the column names is returned (GH6062). • Series and Index now internall share more common operations wasn’t renamed to the group name • Bug in DataFrame.to_csv where setting index=False ignored the header kwarg (GH6186) • Bug in DataFrame.plot and Series.plot, where the legend behave inconsistently when and \r-delimited lines • Bug in python parser with explicit multi-index in row following column header (GH6893) • Bug in Series.rank and DataFrame.rank that caused small floats (<1e-13) to all receive

Van den Bossche • MeeseeksMachine • Tom Augspurger • Will Ayd • William Ayd • jbrockmendel {{ header }} 4 Chapter 1. Whats new in 0.25.2 (October 15, 2019) CHAPTER TWO INSTALLATION The easiest pandas: powerful Python data analysis toolkit, Release 0.25.3 {{ header }} 10 Chapter 2. Installation CHAPTER THREE GETTING STARTED {{ header }} 3.1 Package overview pandas is a Python package providing IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. {{ header }} 3.2 10 minutes to pandas This is a short introduction to pandas, geared mainly for new users

made only in major releases (except for experimental features) See Version Policy for more. {{ header }} 1.2 Enhancements 1.2.1 Using Numba in rolling.apply and expanding.apply We’ve added an engine + {{ header }} 1.10. Contributors 41 pandas: powerful Python data analysis toolkit, Release 1.0.0 42 Chapter 1. What’s new in 1.0.0 (January 29, 2020) CHAPTER TWO GETTING STARTED {{ header }} 2 gotchas. It explains issues surrounding the installa- tion and usage of the above three libraries. {{ header }} 2.1. Installation 47 pandas: powerful Python data analysis toolkit, Release 1.0.0 2.2 Package

read_msgpack() are only guaranteed backwards compatible back to pan- das version 0.20.3 (GH27082) {{ header }} These are the changes in pandas 0.25.0. See release for a full changelog including other versions Bug in DataFrame.to_string() and DataFrame.to_latex() that would lead to incorrect output when the header keyword is used (GH16718) • Bug in read_csv() not properly interpreting the UTF8 encoded filenames when con- verting columns that have missing values (GH25772) • Bug in DataFrame.to_html() where header numbers would ignore display options when rounding (GH17280) 1.6. Bug fixes 29 pandas: powerful

read_msgpack() are only guaranteed backwards compatible back to pan- das version 0.20.3 (GH27082) {{ header }} These are the changes in pandas 0.25.0. See release for a full changelog including other versions Bug in DataFrame.to_string() and DataFrame.to_latex() that would lead to incorrect output when the header keyword is used (GH16718) • Bug in read_csv() not properly interpreting the UTF8 encoded filenames when con- verting columns that have missing values (GH25772) • Bug in DataFrame.to_html() where header numbers would ignore display options when rounding (GH17280) 1.6. Bug fixes 29 pandas: powerful

– Changes to display.precision option – Changes to Categorical.unique – Changes to bool passed as header in Parsers – Other API Changes – Deprecations – Removal of prior version deprecations/changes • Release 0.17.0 loss of information, by specifying which columns/rows make up the MultiIndex in the header and index_col parameters (GH4679) See the documentation for more details. In [31]: df = pd.DataFrame([[1 l 1 2 3 4 k 5 6 7 8 In [33]: df.to_excel('test.xlsx') In [34]: df = pd.read_excel('test.xlsx', header=[0,1], index_col=[0,1]) In [35]: df Out[35]: col1 foo bar col2 a b a b i1 i2 j l 1 2 3 4 k 5