read_table • Added drop_duplicates and duplicated functions for removing duplicate DataFrame rows and check- ing for duplicate rows, respectively (GH319) • Implemented operators ‘&’, ‘|’, ‘^’, ‘-‘ on 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 indexed exactly the same. 7.1.7 Take Methods TODO: Fill Me In 7.1.8 Duplicate Data If you want to indentify and remove duplicate rows in a DataFrame, there are two methods that will help: duplicated

read_table • Added drop_duplicates and duplicated functions for removing duplicate DataFrame rows and check- ing for duplicate rows, respectively (GH319) • Implemented operators ‘&’, ‘|’, ‘^’, ‘-‘ on 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 indexed exactly the same. 7.1.7 Take Methods TODO: Fill Me In 7.1.8 Duplicate Data If you want to indentify and remove duplicate rows in a DataFrame, there are two methods that will help: duplicated

conversion by default. (GH3907) • Add the keyword allow_duplicates to DataFrame.insert to allow a duplicate column to be inserted if True, default is False (same as prior to 0.12) (GH3679) 1.1. v0.12.0 (July clarified (GH3468). – Fix assigning a new index to a duplicate index in a DataFrame would fail (GH3468) – Fix construction of a DataFrame with a duplicate index – ref_locs support to allow duplicative indices non-unique columns (GH3495) – Duplicate indexes with getitem will return items in the correct order (GH3455, GH3457) and handle miss- ing elements like unique indices (GH3561) – Duplicate indexes with and empty

read_table • Added drop_duplicates and duplicated functions for removing duplicate DataFrame rows and check- ing for duplicate rows, respectively (GH319) • Implemented operators ‘&’, ‘|’, ‘^’, ‘-‘ on 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 indexed exactly the same. 7.1.7 Take Methods TODO: Fill Me In 7.1.8 Duplicate Data If you want to indentify and remove duplicate rows in a DataFrame, there are two methods that will help: duplicated

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 10.14 Duplicate Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . h5 File is CLOSED • removed the _quiet attribute, replace by a DuplicateWarning if retrieving duplicate rows from a table (GH4367) • removed the warn argument from open. Instead a PossibleDataLossError conversion by default. (GH3907) • Add the keyword allow_duplicates to DataFrame.insert to allow a duplicate column to be inserted if True, default is False (same as prior to 0.12) (GH3679) • Implement __nonzero__

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 10.14 Duplicate Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . the values to be replaced (GH6342) • str.match ignored the na flag (GH6609). • Bug in take with duplicate columns that were not consolidated (GH6240) • Bug in interpolate changing dtypes (GH6290) • Bug datetime(2013,1,1)), (’date’, ’<=’, datetime(2014,1,1))] (GH6313) • Bug in DataFrame.dropna with duplicate indices (GH6355) • Regression in chained getitem indexing with embedded list-like from 0.12 (GH6394)

Method (Experimental) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355 12.14 Duplicate Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . the values to be replaced (GH6342) • str.match ignored the na flag (GH6609). • Bug in take with duplicate columns that were not consolidated (GH6240) • Bug in interpolate changing dtypes (GH6290) • Bug datetime(2013,1,1)), (’date’, ’<=’, datetime(2014,1,1))] (GH6313) • Bug in DataFrame.dropna with duplicate indices (GH6355) • Regression in chained getitem indexing with embedded list-like from 0.12 (GH6394)

Method (Experimental) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 12.14 Duplicate Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . the values to be replaced (GH6342) • str.match ignored the na flag (GH6609). • Bug in take with duplicate columns that were not consolidated (GH6240) • Bug in interpolate changing dtypes (GH6290) • Bug datetime(2013,1,1)), (’date’, ’<=’, datetime(2014,1,1))] (GH6313) • Bug in DataFrame.dropna with duplicate indices (GH6355) • Regression in chained getitem indexing with embedded list-like from 0.12 (GH6394)

Method (Experimental) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430 13.14 Duplicate Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . function to coerce strings to numbers (possibly with coercion) (GH11133) • pd.merge will now allow duplicate column names if they are not merged upon (GH10639). • pd.pivot will now allow passing index as because of the website url is changed (GH10591). • Bug in read_msgpack where DataFrame to decode has duplicate column names (GH9618) • Bug in io.common.get_filepath_or_buffer which caused reading of valid S3

Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445 2.5.18 Duplicate data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457 2 . . . . . . . . . 625 2.11 Duplicate Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 629 2.11.1 Consequences of Duplicate Labels . . . . . . . . . . . . . . . . . . . . . . 630 2.11.2 Duplicate Label Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632 2.11.3 Disallowing Duplicate Labels . . . . . . . . . . . . . .