method description 'averagedefaultassign the average rank to each entry in the equal group 'minuse the minimum rank for the whole group 'maxuse the maximum rank for the whole group 'firstassign ranks in the order the values appear in the data axis indexes with duplicate values up until now all of the examples 've showed you have had unique axis labels (index valueswhile many pandas functions (like reindexrequire that the labels be uniqueit' not mandatory let' consider small series with duplicate indicesin [ ]obj series(range( )index=[' '' '' '' '' ']in [ ]obj out[ ] the index' is_unique property can tell you whether its values are unique or notin [ ]obj index is_unique out[ ]false data selection is one of the main things that behaves differently with duplicates indexing value with multiple entries returns series while single entries return scalar valuein [ ]obj[' 'out[ ] in [ ]obj[' 'out[ ] the same logic extends to indexing rows in dataframein [ ]df dataframe(np random randn( )index=[' '' '' '' ']in [ ]df out[ ] - - - - - in [ ]df ix[' 'out[ ] getting started with pandas www it-ebooks info