Replace zeros with last value different from zero












2














I have the following dataframe:



print(inventory_df)

dt_op Prod_1 Prod_2 Prod_n
1 10/09/18 5 50 2
2 11/09/18 4 0 0
3 12/09/18 2 0 0
4 13/09/18 0 0 0
5 14/09/18 4 30 1


I would like to change the values equal to zero, with the last value != from zero, in each columns, as:



print(final_inventory_df)

dt_op Prod_1 Prod_2 Prod_n
1 10/09/18 5 50 2
2 11/09/18 4 50 2
3 12/09/18 2 50 2
4 13/09/18 2 50 2
5 14/09/18 4 30 1


How could I do it?










share|improve this question



























    2














    I have the following dataframe:



    print(inventory_df)

    dt_op Prod_1 Prod_2 Prod_n
    1 10/09/18 5 50 2
    2 11/09/18 4 0 0
    3 12/09/18 2 0 0
    4 13/09/18 0 0 0
    5 14/09/18 4 30 1


    I would like to change the values equal to zero, with the last value != from zero, in each columns, as:



    print(final_inventory_df)

    dt_op Prod_1 Prod_2 Prod_n
    1 10/09/18 5 50 2
    2 11/09/18 4 50 2
    3 12/09/18 2 50 2
    4 13/09/18 2 50 2
    5 14/09/18 4 30 1


    How could I do it?










    share|improve this question

























      2












      2








      2







      I have the following dataframe:



      print(inventory_df)

      dt_op Prod_1 Prod_2 Prod_n
      1 10/09/18 5 50 2
      2 11/09/18 4 0 0
      3 12/09/18 2 0 0
      4 13/09/18 0 0 0
      5 14/09/18 4 30 1


      I would like to change the values equal to zero, with the last value != from zero, in each columns, as:



      print(final_inventory_df)

      dt_op Prod_1 Prod_2 Prod_n
      1 10/09/18 5 50 2
      2 11/09/18 4 50 2
      3 12/09/18 2 50 2
      4 13/09/18 2 50 2
      5 14/09/18 4 30 1


      How could I do it?










      share|improve this question













      I have the following dataframe:



      print(inventory_df)

      dt_op Prod_1 Prod_2 Prod_n
      1 10/09/18 5 50 2
      2 11/09/18 4 0 0
      3 12/09/18 2 0 0
      4 13/09/18 0 0 0
      5 14/09/18 4 30 1


      I would like to change the values equal to zero, with the last value != from zero, in each columns, as:



      print(final_inventory_df)

      dt_op Prod_1 Prod_2 Prod_n
      1 10/09/18 5 50 2
      2 11/09/18 4 50 2
      3 12/09/18 2 50 2
      4 13/09/18 2 50 2
      5 14/09/18 4 30 1


      How could I do it?







      python pandas






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 23 '18 at 9:46









      Alessandro CeccarelliAlessandro Ceccarelli

      252211




      252211
























          2 Answers
          2






          active

          oldest

          votes


















          5














          Idea is replace 0 to NaNs by mask and then forward filling them by previous non missing values:



          cols = df.columns.difference(['dt_op'])
          df[cols] = df[cols].mask(df[cols] == 0).ffill().astype(int)


          Similar solution with numpy.where:



          df[cols] = pd.DataFrame(np.where(df[cols] == 0, np.nan, df[cols]), 
          index=df.index,
          columns=cols).ffill().astype(int)


          print (df)
          dt_op Prod_1 Prod_2 Prod_n
          1 10/09/18 5 50 2
          2 11/09/18 4 50 2
          3 12/09/18 2 50 2
          4 13/09/18 2 50 2
          5 14/09/18 4 30 1


          Solution for fun - convert to integer all columns without dt_op:



          d = dict.fromkeys(df.columns.difference(['dt_op']), 'int')
          df = df.mask(df == 0).ffill().astype(d)





          share|improve this answer



















          • 1




            Another excellent piece +1
            – pygo
            Nov 23 '18 at 10:45










          • What if it reports: ValueError: Cannot convert non-finite values (NA or inf) to integer? @jezrael
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:16










          • @AlessandroCeccarelli - It means there is some NaN value, so only remove .astype(int)
            – jezrael
            Nov 23 '18 at 14:17










          • @AlessandroCeccarelli - Because NaN is float type and cannot be casted to integers, so raise error
            – jezrael
            Nov 23 '18 at 14:18






          • 1




            Now it is working properly! Many thanks
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:35



















          2














          Just another option:



          df.iloc[:,1:] = df.iloc[:,1:].replace(0, np.nan).ffill().astype(int)





          share|improve this answer



















          • 1




            This is an excellent show with slicing +1
            – pygo
            Nov 23 '18 at 10:46











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          2 Answers
          2






          active

          oldest

          votes








          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          5














          Idea is replace 0 to NaNs by mask and then forward filling them by previous non missing values:



          cols = df.columns.difference(['dt_op'])
          df[cols] = df[cols].mask(df[cols] == 0).ffill().astype(int)


          Similar solution with numpy.where:



          df[cols] = pd.DataFrame(np.where(df[cols] == 0, np.nan, df[cols]), 
          index=df.index,
          columns=cols).ffill().astype(int)


          print (df)
          dt_op Prod_1 Prod_2 Prod_n
          1 10/09/18 5 50 2
          2 11/09/18 4 50 2
          3 12/09/18 2 50 2
          4 13/09/18 2 50 2
          5 14/09/18 4 30 1


          Solution for fun - convert to integer all columns without dt_op:



          d = dict.fromkeys(df.columns.difference(['dt_op']), 'int')
          df = df.mask(df == 0).ffill().astype(d)





          share|improve this answer



















          • 1




            Another excellent piece +1
            – pygo
            Nov 23 '18 at 10:45










          • What if it reports: ValueError: Cannot convert non-finite values (NA or inf) to integer? @jezrael
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:16










          • @AlessandroCeccarelli - It means there is some NaN value, so only remove .astype(int)
            – jezrael
            Nov 23 '18 at 14:17










          • @AlessandroCeccarelli - Because NaN is float type and cannot be casted to integers, so raise error
            – jezrael
            Nov 23 '18 at 14:18






          • 1




            Now it is working properly! Many thanks
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:35
















          5














          Idea is replace 0 to NaNs by mask and then forward filling them by previous non missing values:



          cols = df.columns.difference(['dt_op'])
          df[cols] = df[cols].mask(df[cols] == 0).ffill().astype(int)


          Similar solution with numpy.where:



          df[cols] = pd.DataFrame(np.where(df[cols] == 0, np.nan, df[cols]), 
          index=df.index,
          columns=cols).ffill().astype(int)


          print (df)
          dt_op Prod_1 Prod_2 Prod_n
          1 10/09/18 5 50 2
          2 11/09/18 4 50 2
          3 12/09/18 2 50 2
          4 13/09/18 2 50 2
          5 14/09/18 4 30 1


          Solution for fun - convert to integer all columns without dt_op:



          d = dict.fromkeys(df.columns.difference(['dt_op']), 'int')
          df = df.mask(df == 0).ffill().astype(d)





          share|improve this answer



















          • 1




            Another excellent piece +1
            – pygo
            Nov 23 '18 at 10:45










          • What if it reports: ValueError: Cannot convert non-finite values (NA or inf) to integer? @jezrael
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:16










          • @AlessandroCeccarelli - It means there is some NaN value, so only remove .astype(int)
            – jezrael
            Nov 23 '18 at 14:17










          • @AlessandroCeccarelli - Because NaN is float type and cannot be casted to integers, so raise error
            – jezrael
            Nov 23 '18 at 14:18






          • 1




            Now it is working properly! Many thanks
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:35














          5












          5








          5






          Idea is replace 0 to NaNs by mask and then forward filling them by previous non missing values:



          cols = df.columns.difference(['dt_op'])
          df[cols] = df[cols].mask(df[cols] == 0).ffill().astype(int)


          Similar solution with numpy.where:



          df[cols] = pd.DataFrame(np.where(df[cols] == 0, np.nan, df[cols]), 
          index=df.index,
          columns=cols).ffill().astype(int)


          print (df)
          dt_op Prod_1 Prod_2 Prod_n
          1 10/09/18 5 50 2
          2 11/09/18 4 50 2
          3 12/09/18 2 50 2
          4 13/09/18 2 50 2
          5 14/09/18 4 30 1


          Solution for fun - convert to integer all columns without dt_op:



          d = dict.fromkeys(df.columns.difference(['dt_op']), 'int')
          df = df.mask(df == 0).ffill().astype(d)





          share|improve this answer














          Idea is replace 0 to NaNs by mask and then forward filling them by previous non missing values:



          cols = df.columns.difference(['dt_op'])
          df[cols] = df[cols].mask(df[cols] == 0).ffill().astype(int)


          Similar solution with numpy.where:



          df[cols] = pd.DataFrame(np.where(df[cols] == 0, np.nan, df[cols]), 
          index=df.index,
          columns=cols).ffill().astype(int)


          print (df)
          dt_op Prod_1 Prod_2 Prod_n
          1 10/09/18 5 50 2
          2 11/09/18 4 50 2
          3 12/09/18 2 50 2
          4 13/09/18 2 50 2
          5 14/09/18 4 30 1


          Solution for fun - convert to integer all columns without dt_op:



          d = dict.fromkeys(df.columns.difference(['dt_op']), 'int')
          df = df.mask(df == 0).ffill().astype(d)






          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 23 '18 at 9:53

























          answered Nov 23 '18 at 9:47









          jezraeljezrael

          323k23265342




          323k23265342








          • 1




            Another excellent piece +1
            – pygo
            Nov 23 '18 at 10:45










          • What if it reports: ValueError: Cannot convert non-finite values (NA or inf) to integer? @jezrael
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:16










          • @AlessandroCeccarelli - It means there is some NaN value, so only remove .astype(int)
            – jezrael
            Nov 23 '18 at 14:17










          • @AlessandroCeccarelli - Because NaN is float type and cannot be casted to integers, so raise error
            – jezrael
            Nov 23 '18 at 14:18






          • 1




            Now it is working properly! Many thanks
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:35














          • 1




            Another excellent piece +1
            – pygo
            Nov 23 '18 at 10:45










          • What if it reports: ValueError: Cannot convert non-finite values (NA or inf) to integer? @jezrael
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:16










          • @AlessandroCeccarelli - It means there is some NaN value, so only remove .astype(int)
            – jezrael
            Nov 23 '18 at 14:17










          • @AlessandroCeccarelli - Because NaN is float type and cannot be casted to integers, so raise error
            – jezrael
            Nov 23 '18 at 14:18






          • 1




            Now it is working properly! Many thanks
            – Alessandro Ceccarelli
            Nov 23 '18 at 14:35








          1




          1




          Another excellent piece +1
          – pygo
          Nov 23 '18 at 10:45




          Another excellent piece +1
          – pygo
          Nov 23 '18 at 10:45












          What if it reports: ValueError: Cannot convert non-finite values (NA or inf) to integer? @jezrael
          – Alessandro Ceccarelli
          Nov 23 '18 at 14:16




          What if it reports: ValueError: Cannot convert non-finite values (NA or inf) to integer? @jezrael
          – Alessandro Ceccarelli
          Nov 23 '18 at 14:16












          @AlessandroCeccarelli - It means there is some NaN value, so only remove .astype(int)
          – jezrael
          Nov 23 '18 at 14:17




          @AlessandroCeccarelli - It means there is some NaN value, so only remove .astype(int)
          – jezrael
          Nov 23 '18 at 14:17












          @AlessandroCeccarelli - Because NaN is float type and cannot be casted to integers, so raise error
          – jezrael
          Nov 23 '18 at 14:18




          @AlessandroCeccarelli - Because NaN is float type and cannot be casted to integers, so raise error
          – jezrael
          Nov 23 '18 at 14:18




          1




          1




          Now it is working properly! Many thanks
          – Alessandro Ceccarelli
          Nov 23 '18 at 14:35




          Now it is working properly! Many thanks
          – Alessandro Ceccarelli
          Nov 23 '18 at 14:35













          2














          Just another option:



          df.iloc[:,1:] = df.iloc[:,1:].replace(0, np.nan).ffill().astype(int)





          share|improve this answer



















          • 1




            This is an excellent show with slicing +1
            – pygo
            Nov 23 '18 at 10:46
















          2














          Just another option:



          df.iloc[:,1:] = df.iloc[:,1:].replace(0, np.nan).ffill().astype(int)





          share|improve this answer



















          • 1




            This is an excellent show with slicing +1
            – pygo
            Nov 23 '18 at 10:46














          2












          2








          2






          Just another option:



          df.iloc[:,1:] = df.iloc[:,1:].replace(0, np.nan).ffill().astype(int)





          share|improve this answer














          Just another option:



          df.iloc[:,1:] = df.iloc[:,1:].replace(0, np.nan).ffill().astype(int)






          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 23 '18 at 10:47

























          answered Nov 23 '18 at 10:22









          JoeJoe

          5,89621129




          5,89621129








          • 1




            This is an excellent show with slicing +1
            – pygo
            Nov 23 '18 at 10:46














          • 1




            This is an excellent show with slicing +1
            – pygo
            Nov 23 '18 at 10:46








          1




          1




          This is an excellent show with slicing +1
          – pygo
          Nov 23 '18 at 10:46




          This is an excellent show with slicing +1
          – pygo
          Nov 23 '18 at 10:46


















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