Looping over pandas DataFrame





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I have a weird issue that the result doesn't change for each iteration. The code is the following:



import pandas as pd
import numpy as np

X = np.arange(10,100)
Y = X[::-1]
Z = np.array([X,Y]).T

df = pd.DataFrame(Z ,columns = ['col1','col2'])
dif = df['col1'] - df['col2']

for gap in range(100):
Up = dif > gap
Down = dif < -gap

df.loc[Up,'predict'] = 'Up'
df.loc[Down,'predict'] = 'Down'

df_result = df.dropna()
Total = df.shape[0]
count = df_result.shape[0]
ratio = count/Total
print(f'Total: {Total}; count: {count}; ratio: {ratio}')


The result is always



Total: 90; count: 90; ratio: 1.0


when it shouldn't be. Thank you in advance










share|improve this question





























    0















    I have a weird issue that the result doesn't change for each iteration. The code is the following:



    import pandas as pd
    import numpy as np

    X = np.arange(10,100)
    Y = X[::-1]
    Z = np.array([X,Y]).T

    df = pd.DataFrame(Z ,columns = ['col1','col2'])
    dif = df['col1'] - df['col2']

    for gap in range(100):
    Up = dif > gap
    Down = dif < -gap

    df.loc[Up,'predict'] = 'Up'
    df.loc[Down,'predict'] = 'Down'

    df_result = df.dropna()
    Total = df.shape[0]
    count = df_result.shape[0]
    ratio = count/Total
    print(f'Total: {Total}; count: {count}; ratio: {ratio}')


    The result is always



    Total: 90; count: 90; ratio: 1.0


    when it shouldn't be. Thank you in advance










    share|improve this question

























      0












      0








      0








      I have a weird issue that the result doesn't change for each iteration. The code is the following:



      import pandas as pd
      import numpy as np

      X = np.arange(10,100)
      Y = X[::-1]
      Z = np.array([X,Y]).T

      df = pd.DataFrame(Z ,columns = ['col1','col2'])
      dif = df['col1'] - df['col2']

      for gap in range(100):
      Up = dif > gap
      Down = dif < -gap

      df.loc[Up,'predict'] = 'Up'
      df.loc[Down,'predict'] = 'Down'

      df_result = df.dropna()
      Total = df.shape[0]
      count = df_result.shape[0]
      ratio = count/Total
      print(f'Total: {Total}; count: {count}; ratio: {ratio}')


      The result is always



      Total: 90; count: 90; ratio: 1.0


      when it shouldn't be. Thank you in advance










      share|improve this question














      I have a weird issue that the result doesn't change for each iteration. The code is the following:



      import pandas as pd
      import numpy as np

      X = np.arange(10,100)
      Y = X[::-1]
      Z = np.array([X,Y]).T

      df = pd.DataFrame(Z ,columns = ['col1','col2'])
      dif = df['col1'] - df['col2']

      for gap in range(100):
      Up = dif > gap
      Down = dif < -gap

      df.loc[Up,'predict'] = 'Up'
      df.loc[Down,'predict'] = 'Down'

      df_result = df.dropna()
      Total = df.shape[0]
      count = df_result.shape[0]
      ratio = count/Total
      print(f'Total: {Total}; count: {count}; ratio: {ratio}')


      The result is always



      Total: 90; count: 90; ratio: 1.0


      when it shouldn't be. Thank you in advance







      python-3.x pandas loops numpy na






      share|improve this question













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      share|improve this question










      asked Nov 25 '18 at 9:11









      mathguymathguy

      1197




      1197
























          1 Answer
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          1














          Found the root of the problem 5 mins after posting this question. I just needed to reset the dataFrame to the original to fix the problem.



          import pandas as pd
          import numpy as np

          X = np.arange(10,100)
          Y = X[::-1]
          Z = np.array([X,Y]).T

          df = pd.DataFrame(Z ,columns = ['col1','col2'])
          df2 = df.copy()#added this line to preserve the original df
          dif = df['col1'] - df['col2']

          for gap in range(100):
          df = df2.copy()#reset the altered df back to the original
          Up = dif > gap
          Down = dif < -gap

          df.loc[Up,'predict'] = 'Up'
          df.loc[Down,'predict'] = 'Down'

          df_result = df.dropna()
          Total = df.shape[0]
          count = df_result.shape[0]
          ratio = count/Total
          print(f'Total: {Total}; count: {count}; ratio: {ratio}')





          share|improve this answer
























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            1 Answer
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            active

            oldest

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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            1














            Found the root of the problem 5 mins after posting this question. I just needed to reset the dataFrame to the original to fix the problem.



            import pandas as pd
            import numpy as np

            X = np.arange(10,100)
            Y = X[::-1]
            Z = np.array([X,Y]).T

            df = pd.DataFrame(Z ,columns = ['col1','col2'])
            df2 = df.copy()#added this line to preserve the original df
            dif = df['col1'] - df['col2']

            for gap in range(100):
            df = df2.copy()#reset the altered df back to the original
            Up = dif > gap
            Down = dif < -gap

            df.loc[Up,'predict'] = 'Up'
            df.loc[Down,'predict'] = 'Down'

            df_result = df.dropna()
            Total = df.shape[0]
            count = df_result.shape[0]
            ratio = count/Total
            print(f'Total: {Total}; count: {count}; ratio: {ratio}')





            share|improve this answer




























              1














              Found the root of the problem 5 mins after posting this question. I just needed to reset the dataFrame to the original to fix the problem.



              import pandas as pd
              import numpy as np

              X = np.arange(10,100)
              Y = X[::-1]
              Z = np.array([X,Y]).T

              df = pd.DataFrame(Z ,columns = ['col1','col2'])
              df2 = df.copy()#added this line to preserve the original df
              dif = df['col1'] - df['col2']

              for gap in range(100):
              df = df2.copy()#reset the altered df back to the original
              Up = dif > gap
              Down = dif < -gap

              df.loc[Up,'predict'] = 'Up'
              df.loc[Down,'predict'] = 'Down'

              df_result = df.dropna()
              Total = df.shape[0]
              count = df_result.shape[0]
              ratio = count/Total
              print(f'Total: {Total}; count: {count}; ratio: {ratio}')





              share|improve this answer


























                1












                1








                1







                Found the root of the problem 5 mins after posting this question. I just needed to reset the dataFrame to the original to fix the problem.



                import pandas as pd
                import numpy as np

                X = np.arange(10,100)
                Y = X[::-1]
                Z = np.array([X,Y]).T

                df = pd.DataFrame(Z ,columns = ['col1','col2'])
                df2 = df.copy()#added this line to preserve the original df
                dif = df['col1'] - df['col2']

                for gap in range(100):
                df = df2.copy()#reset the altered df back to the original
                Up = dif > gap
                Down = dif < -gap

                df.loc[Up,'predict'] = 'Up'
                df.loc[Down,'predict'] = 'Down'

                df_result = df.dropna()
                Total = df.shape[0]
                count = df_result.shape[0]
                ratio = count/Total
                print(f'Total: {Total}; count: {count}; ratio: {ratio}')





                share|improve this answer













                Found the root of the problem 5 mins after posting this question. I just needed to reset the dataFrame to the original to fix the problem.



                import pandas as pd
                import numpy as np

                X = np.arange(10,100)
                Y = X[::-1]
                Z = np.array([X,Y]).T

                df = pd.DataFrame(Z ,columns = ['col1','col2'])
                df2 = df.copy()#added this line to preserve the original df
                dif = df['col1'] - df['col2']

                for gap in range(100):
                df = df2.copy()#reset the altered df back to the original
                Up = dif > gap
                Down = dif < -gap

                df.loc[Up,'predict'] = 'Up'
                df.loc[Down,'predict'] = 'Down'

                df_result = df.dropna()
                Total = df.shape[0]
                count = df_result.shape[0]
                ratio = count/Total
                print(f'Total: {Total}; count: {count}; ratio: {ratio}')






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 25 '18 at 9:20









                mathguymathguy

                1197




                1197
































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