Pandas - append column with sum of even row values












3















I have a dataframe and I want a new column with sum of other columns in the same row. Criteria is I want Nan if the sum is odd and the sum if the value is even.



df = pd.DataFrame([[1, 8, 7, 2],
[8, 5, 9, 4],
[1, -5, 3, -2]], columns=list('pqrs'))
df

p q r s
0 1 8 7 2
1 8 5 9 4
2 1 -5 3 -2

Expected output:
p q r s t
0 1 8 7 2 18.0
1 8 5 9 4 26.0
2 1 -5 3 -2 NaN









share|improve this question





























    3















    I have a dataframe and I want a new column with sum of other columns in the same row. Criteria is I want Nan if the sum is odd and the sum if the value is even.



    df = pd.DataFrame([[1, 8, 7, 2],
    [8, 5, 9, 4],
    [1, -5, 3, -2]], columns=list('pqrs'))
    df

    p q r s
    0 1 8 7 2
    1 8 5 9 4
    2 1 -5 3 -2

    Expected output:
    p q r s t
    0 1 8 7 2 18.0
    1 8 5 9 4 26.0
    2 1 -5 3 -2 NaN









    share|improve this question



























      3












      3








      3








      I have a dataframe and I want a new column with sum of other columns in the same row. Criteria is I want Nan if the sum is odd and the sum if the value is even.



      df = pd.DataFrame([[1, 8, 7, 2],
      [8, 5, 9, 4],
      [1, -5, 3, -2]], columns=list('pqrs'))
      df

      p q r s
      0 1 8 7 2
      1 8 5 9 4
      2 1 -5 3 -2

      Expected output:
      p q r s t
      0 1 8 7 2 18.0
      1 8 5 9 4 26.0
      2 1 -5 3 -2 NaN









      share|improve this question
















      I have a dataframe and I want a new column with sum of other columns in the same row. Criteria is I want Nan if the sum is odd and the sum if the value is even.



      df = pd.DataFrame([[1, 8, 7, 2],
      [8, 5, 9, 4],
      [1, -5, 3, -2]], columns=list('pqrs'))
      df

      p q r s
      0 1 8 7 2
      1 8 5 9 4
      2 1 -5 3 -2

      Expected output:
      p q r s t
      0 1 8 7 2 18.0
      1 8 5 9 4 26.0
      2 1 -5 3 -2 NaN






      python pandas dataframe sum






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      edited Nov 28 '18 at 5:35









      Anand

      116




      116










      asked Nov 28 '18 at 5:22







      user10715091































          1 Answer
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          2














          Using np.where



          df['new']=np.where(df.sum(1)%2==0,df.sum(1),np.nan)
          df
          p q r s new
          0 1 8 7 2 18.0
          1 8 5 9 4 26.0
          2 1 -5 3 -2 NaN





          share|improve this answer























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            1 Answer
            1






            active

            oldest

            votes








            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            2














            Using np.where



            df['new']=np.where(df.sum(1)%2==0,df.sum(1),np.nan)
            df
            p q r s new
            0 1 8 7 2 18.0
            1 8 5 9 4 26.0
            2 1 -5 3 -2 NaN





            share|improve this answer




























              2














              Using np.where



              df['new']=np.where(df.sum(1)%2==0,df.sum(1),np.nan)
              df
              p q r s new
              0 1 8 7 2 18.0
              1 8 5 9 4 26.0
              2 1 -5 3 -2 NaN





              share|improve this answer


























                2












                2








                2







                Using np.where



                df['new']=np.where(df.sum(1)%2==0,df.sum(1),np.nan)
                df
                p q r s new
                0 1 8 7 2 18.0
                1 8 5 9 4 26.0
                2 1 -5 3 -2 NaN





                share|improve this answer













                Using np.where



                df['new']=np.where(df.sum(1)%2==0,df.sum(1),np.nan)
                df
                p q r s new
                0 1 8 7 2 18.0
                1 8 5 9 4 26.0
                2 1 -5 3 -2 NaN






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 28 '18 at 5:25









                Wen-BenWen-Ben

                117k83469




                117k83469
































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