python - How to convert Panda's columns into an index and a header when index column has duplicates -

i’d convert dataframe, df, similar one:

pidm            | course          | grade 1               | mat1            | b 1               | phy2            | c 2               | mat1            | 2               | mat2            | b 2               | phe2            | 

to following format:

pidm     |  mat1      | phy2    |  mat2  | phy 2   1        |    b       |    c    |  nan   |   nan 2        |          |    nan  |  b     |   

i assuming like:

df2 = df.pivot(index='pidm', columns=‘course’, values = ‘grade) 

but receive error stating have duplicate indices. thank help.

you can use pivot_table aggregate function join:

df2 = df.pivot_table(index='pidm', columns='course', values = 'grade', aggfunc=', '.join) print (df2) course mat1  mat2  phe2  phy2 pidm                          1         b  none  none     c 2             b      none