Pandas Groupby using multiple criteria on different axis












2














I have a df DataFrame like :



      | A | B | A_ | B_ |COMMON|
--------------------------------
0 | 1 | 3 | 0 | 1 | a |
--------------------------------
1 | 8 | 5 | 4 | 0 | a |
--------------------------------
2 | 3 | 6 | 2 | 4 | b |
--------------------------------
3 | 9 | 9 | 1 | 7 | b |


And I want to group all columns X with X_ for all letters A,B,... (let's say, the group is called X as well), and group as well using COMMON. I would like to apply later function like std() to all the grouped values.



So the result would look like:



COMMON  |  A     |  B     |
---------------------------
a |std(...)|std(...)|
---------------------------
b |std(...)|std(...)|


I have been able to group either one or the other, using df.groupby(['COMMMON']) for one criteria and .groupby(mapping_function, axis=1) for the other one, but how do I use them together?



Another alternative for an intermediate step would be to concatenate individual columns so that I would get:



      | A | B |COMMON|
----------------------
0 | 1 | 3 |a |
---------------------
1 | 8 | 5 |a |
---------------------
2 | 3 | 6 |b |
---------------------
3 | 9 | 9 |b |
---------------------
0 | 0 | 1 |a |
---------------------
1 | 4 | 0 |a |
---------------------
2 | 2 | 4 |b |
---------------------
3 | 1 | 7 |b |


But I also don't know how to do that.
Also as you might see, I don't really care about the index.



Thank you for your help!










share|improve this question



























    2














    I have a df DataFrame like :



          | A | B | A_ | B_ |COMMON|
    --------------------------------
    0 | 1 | 3 | 0 | 1 | a |
    --------------------------------
    1 | 8 | 5 | 4 | 0 | a |
    --------------------------------
    2 | 3 | 6 | 2 | 4 | b |
    --------------------------------
    3 | 9 | 9 | 1 | 7 | b |


    And I want to group all columns X with X_ for all letters A,B,... (let's say, the group is called X as well), and group as well using COMMON. I would like to apply later function like std() to all the grouped values.



    So the result would look like:



    COMMON  |  A     |  B     |
    ---------------------------
    a |std(...)|std(...)|
    ---------------------------
    b |std(...)|std(...)|


    I have been able to group either one or the other, using df.groupby(['COMMMON']) for one criteria and .groupby(mapping_function, axis=1) for the other one, but how do I use them together?



    Another alternative for an intermediate step would be to concatenate individual columns so that I would get:



          | A | B |COMMON|
    ----------------------
    0 | 1 | 3 |a |
    ---------------------
    1 | 8 | 5 |a |
    ---------------------
    2 | 3 | 6 |b |
    ---------------------
    3 | 9 | 9 |b |
    ---------------------
    0 | 0 | 1 |a |
    ---------------------
    1 | 4 | 0 |a |
    ---------------------
    2 | 2 | 4 |b |
    ---------------------
    3 | 1 | 7 |b |


    But I also don't know how to do that.
    Also as you might see, I don't really care about the index.



    Thank you for your help!










    share|improve this question

























      2












      2








      2


      1





      I have a df DataFrame like :



            | A | B | A_ | B_ |COMMON|
      --------------------------------
      0 | 1 | 3 | 0 | 1 | a |
      --------------------------------
      1 | 8 | 5 | 4 | 0 | a |
      --------------------------------
      2 | 3 | 6 | 2 | 4 | b |
      --------------------------------
      3 | 9 | 9 | 1 | 7 | b |


      And I want to group all columns X with X_ for all letters A,B,... (let's say, the group is called X as well), and group as well using COMMON. I would like to apply later function like std() to all the grouped values.



      So the result would look like:



      COMMON  |  A     |  B     |
      ---------------------------
      a |std(...)|std(...)|
      ---------------------------
      b |std(...)|std(...)|


      I have been able to group either one or the other, using df.groupby(['COMMMON']) for one criteria and .groupby(mapping_function, axis=1) for the other one, but how do I use them together?



      Another alternative for an intermediate step would be to concatenate individual columns so that I would get:



            | A | B |COMMON|
      ----------------------
      0 | 1 | 3 |a |
      ---------------------
      1 | 8 | 5 |a |
      ---------------------
      2 | 3 | 6 |b |
      ---------------------
      3 | 9 | 9 |b |
      ---------------------
      0 | 0 | 1 |a |
      ---------------------
      1 | 4 | 0 |a |
      ---------------------
      2 | 2 | 4 |b |
      ---------------------
      3 | 1 | 7 |b |


      But I also don't know how to do that.
      Also as you might see, I don't really care about the index.



      Thank you for your help!










      share|improve this question













      I have a df DataFrame like :



            | A | B | A_ | B_ |COMMON|
      --------------------------------
      0 | 1 | 3 | 0 | 1 | a |
      --------------------------------
      1 | 8 | 5 | 4 | 0 | a |
      --------------------------------
      2 | 3 | 6 | 2 | 4 | b |
      --------------------------------
      3 | 9 | 9 | 1 | 7 | b |


      And I want to group all columns X with X_ for all letters A,B,... (let's say, the group is called X as well), and group as well using COMMON. I would like to apply later function like std() to all the grouped values.



      So the result would look like:



      COMMON  |  A     |  B     |
      ---------------------------
      a |std(...)|std(...)|
      ---------------------------
      b |std(...)|std(...)|


      I have been able to group either one or the other, using df.groupby(['COMMMON']) for one criteria and .groupby(mapping_function, axis=1) for the other one, but how do I use them together?



      Another alternative for an intermediate step would be to concatenate individual columns so that I would get:



            | A | B |COMMON|
      ----------------------
      0 | 1 | 3 |a |
      ---------------------
      1 | 8 | 5 |a |
      ---------------------
      2 | 3 | 6 |b |
      ---------------------
      3 | 9 | 9 |b |
      ---------------------
      0 | 0 | 1 |a |
      ---------------------
      1 | 4 | 0 |a |
      ---------------------
      2 | 2 | 4 |b |
      ---------------------
      3 | 1 | 7 |b |


      But I also don't know how to do that.
      Also as you might see, I don't really care about the index.



      Thank you for your help!







      python pandas pandas-groupby






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      asked Nov 12 at 14:22









      cduguet

      311214




      311214
























          3 Answers
          3






          active

          oldest

          votes


















          7














          You can reshape first by melt with removing _ from column names (for better performance, because strip only few values) with pivot_table:



          df = (df.rename(columns=lambda x: x.strip('_'))
          .melt('COMMON')
          .pivot_table(index='COMMON',columns='variable', values='value', aggfunc='std'))

          print (df)
          variable A B
          COMMON
          a 3.593976 2.217356
          b 3.593976 2.081666





          share|improve this answer



















          • 2




            Nice pivot :-) .
            – W-B
            Nov 12 at 14:33



















          5














          IIUC



          df.melt('COMMON').assign(variable=lambda x : x['variable'].str.rstrip('_')).
          groupby(['COMMON','variable']).value.std().unstack()
          Out[18]:
          variable A B
          COMMON
          a 3.593976 2.217356
          b 3.593976 2.081666





          share|improve this answer





























            2














            Just groupby



            h = lambda x: x[-1][0]

            df.set_index('COMMON', append=True).stack().groupby(['COMMON', h]).std().unstack()

            A B
            COMMON
            a 3.593976 2.217356
            b 3.593976 2.081666





            share|improve this answer























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              3 Answers
              3






              active

              oldest

              votes








              3 Answers
              3






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes









              7














              You can reshape first by melt with removing _ from column names (for better performance, because strip only few values) with pivot_table:



              df = (df.rename(columns=lambda x: x.strip('_'))
              .melt('COMMON')
              .pivot_table(index='COMMON',columns='variable', values='value', aggfunc='std'))

              print (df)
              variable A B
              COMMON
              a 3.593976 2.217356
              b 3.593976 2.081666





              share|improve this answer



















              • 2




                Nice pivot :-) .
                – W-B
                Nov 12 at 14:33
















              7














              You can reshape first by melt with removing _ from column names (for better performance, because strip only few values) with pivot_table:



              df = (df.rename(columns=lambda x: x.strip('_'))
              .melt('COMMON')
              .pivot_table(index='COMMON',columns='variable', values='value', aggfunc='std'))

              print (df)
              variable A B
              COMMON
              a 3.593976 2.217356
              b 3.593976 2.081666





              share|improve this answer



















              • 2




                Nice pivot :-) .
                – W-B
                Nov 12 at 14:33














              7












              7








              7






              You can reshape first by melt with removing _ from column names (for better performance, because strip only few values) with pivot_table:



              df = (df.rename(columns=lambda x: x.strip('_'))
              .melt('COMMON')
              .pivot_table(index='COMMON',columns='variable', values='value', aggfunc='std'))

              print (df)
              variable A B
              COMMON
              a 3.593976 2.217356
              b 3.593976 2.081666





              share|improve this answer














              You can reshape first by melt with removing _ from column names (for better performance, because strip only few values) with pivot_table:



              df = (df.rename(columns=lambda x: x.strip('_'))
              .melt('COMMON')
              .pivot_table(index='COMMON',columns='variable', values='value', aggfunc='std'))

              print (df)
              variable A B
              COMMON
              a 3.593976 2.217356
              b 3.593976 2.081666






              share|improve this answer














              share|improve this answer



              share|improve this answer








              edited Nov 12 at 14:45

























              answered Nov 12 at 14:29









              jezrael

              319k22258336




              319k22258336








              • 2




                Nice pivot :-) .
                – W-B
                Nov 12 at 14:33














              • 2




                Nice pivot :-) .
                – W-B
                Nov 12 at 14:33








              2




              2




              Nice pivot :-) .
              – W-B
              Nov 12 at 14:33




              Nice pivot :-) .
              – W-B
              Nov 12 at 14:33













              5














              IIUC



              df.melt('COMMON').assign(variable=lambda x : x['variable'].str.rstrip('_')).
              groupby(['COMMON','variable']).value.std().unstack()
              Out[18]:
              variable A B
              COMMON
              a 3.593976 2.217356
              b 3.593976 2.081666





              share|improve this answer


























                5














                IIUC



                df.melt('COMMON').assign(variable=lambda x : x['variable'].str.rstrip('_')).
                groupby(['COMMON','variable']).value.std().unstack()
                Out[18]:
                variable A B
                COMMON
                a 3.593976 2.217356
                b 3.593976 2.081666





                share|improve this answer
























                  5












                  5








                  5






                  IIUC



                  df.melt('COMMON').assign(variable=lambda x : x['variable'].str.rstrip('_')).
                  groupby(['COMMON','variable']).value.std().unstack()
                  Out[18]:
                  variable A B
                  COMMON
                  a 3.593976 2.217356
                  b 3.593976 2.081666





                  share|improve this answer












                  IIUC



                  df.melt('COMMON').assign(variable=lambda x : x['variable'].str.rstrip('_')).
                  groupby(['COMMON','variable']).value.std().unstack()
                  Out[18]:
                  variable A B
                  COMMON
                  a 3.593976 2.217356
                  b 3.593976 2.081666






                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Nov 12 at 14:30









                  W-B

                  99.7k73163




                  99.7k73163























                      2














                      Just groupby



                      h = lambda x: x[-1][0]

                      df.set_index('COMMON', append=True).stack().groupby(['COMMON', h]).std().unstack()

                      A B
                      COMMON
                      a 3.593976 2.217356
                      b 3.593976 2.081666





                      share|improve this answer




























                        2














                        Just groupby



                        h = lambda x: x[-1][0]

                        df.set_index('COMMON', append=True).stack().groupby(['COMMON', h]).std().unstack()

                        A B
                        COMMON
                        a 3.593976 2.217356
                        b 3.593976 2.081666





                        share|improve this answer


























                          2












                          2








                          2






                          Just groupby



                          h = lambda x: x[-1][0]

                          df.set_index('COMMON', append=True).stack().groupby(['COMMON', h]).std().unstack()

                          A B
                          COMMON
                          a 3.593976 2.217356
                          b 3.593976 2.081666





                          share|improve this answer














                          Just groupby



                          h = lambda x: x[-1][0]

                          df.set_index('COMMON', append=True).stack().groupby(['COMMON', h]).std().unstack()

                          A B
                          COMMON
                          a 3.593976 2.217356
                          b 3.593976 2.081666






                          share|improve this answer














                          share|improve this answer



                          share|improve this answer








                          edited Nov 12 at 15:06

























                          answered Nov 12 at 14:56









                          piRSquared

                          151k22143285




                          151k22143285






























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