two three four five ohio ohio ohio nevada nevada nan - nan - - assigning column that doesn' exist will create new column the del keyword will delete columns as with dictin [ ]frame ['eastern'frame state ='ohioin [ ]frame out[ ]year state one ohio two ohio three ohio four nevada five nevada pop debt eastern nan true - true nan true - false - false in [ ]del frame ['eastern'in [ ]frame columns out[ ]index([yearstatepopdebt]dtype=objectthe column returned when indexing dataframe is view on the underlying datanot copy thusany in-place modifications to the series will be reflected in the dataframe the column can be explicitly copied using the series' copy method another common form of data is nested dict of dicts formatin [ ]pop {'nevada'{ }'ohio'{ }if passed to dataframeit will interpret the outer dict keys as the columns and the inner keys as the row indicesin [ ]frame dataframe(popin [ ]frame out[ ]nevada ohio nan of course you can always transpose the resultin [ ]frame out[ ] nevada nan ohio getting started with pandas www it-ebooks info