Custom mapping of categorical to numeric values












0















I have object type columns that have categorical values example 15-16 Years, 17-23 Years ..... I have converted them to category and then cat.codes. However,the coding values start from 0 for the first group 0-4 years and I want the coding to start from 1 ie 0-4->1, 5-12-> and @@->NaN
The suggested solution of using dictionary mapping still has issues. Following is mcve



import pandas as pd
data = ['0-4 Years', '5-12 Years','13-18 Years', '19-21 Years','22-25 Years','26-29 Years','30-35 Years',
'36-41 Years','42-45 Years','46-49 Years','50-55 Years', '56-63 Years']
df = pd.DataFrame(data,columns=['Age'],dtype=object)
df['Age']=df['Age'].astype('category')
cats = dict(enumerate(df['Age'].cat.categories, 2))
df['Age']=df['Age'].cat.codes.map(cats).astype('category')
df['Age']


and here is the output, as you can see if I change the enumeration start other than 0, there is an issue with values as NaN. Secondly the column is not coded either:



df['Age']
0 NaN
1 36-41 Years
2 NaN
3 NaN
4 0-4 Years
5 13-18 Years
6 19-21 Years
7 22-25 Years
8 26-29 Years
9 30-35 Years
10 42-45 Years
11 46-49 Years
Name: Age, dtype: category
Categories (9, object): [0-4 Years, 13-18 Years, 19-21 Years, 22-25 Years, ..., 30-35 Years, 36-41 Years, 42-45 Years, 46-49 Years]


How to fix this.










share|improve this question





























    0















    I have object type columns that have categorical values example 15-16 Years, 17-23 Years ..... I have converted them to category and then cat.codes. However,the coding values start from 0 for the first group 0-4 years and I want the coding to start from 1 ie 0-4->1, 5-12-> and @@->NaN
    The suggested solution of using dictionary mapping still has issues. Following is mcve



    import pandas as pd
    data = ['0-4 Years', '5-12 Years','13-18 Years', '19-21 Years','22-25 Years','26-29 Years','30-35 Years',
    '36-41 Years','42-45 Years','46-49 Years','50-55 Years', '56-63 Years']
    df = pd.DataFrame(data,columns=['Age'],dtype=object)
    df['Age']=df['Age'].astype('category')
    cats = dict(enumerate(df['Age'].cat.categories, 2))
    df['Age']=df['Age'].cat.codes.map(cats).astype('category')
    df['Age']


    and here is the output, as you can see if I change the enumeration start other than 0, there is an issue with values as NaN. Secondly the column is not coded either:



    df['Age']
    0 NaN
    1 36-41 Years
    2 NaN
    3 NaN
    4 0-4 Years
    5 13-18 Years
    6 19-21 Years
    7 22-25 Years
    8 26-29 Years
    9 30-35 Years
    10 42-45 Years
    11 46-49 Years
    Name: Age, dtype: category
    Categories (9, object): [0-4 Years, 13-18 Years, 19-21 Years, 22-25 Years, ..., 30-35 Years, 36-41 Years, 42-45 Years, 46-49 Years]


    How to fix this.










    share|improve this question



























      0












      0








      0








      I have object type columns that have categorical values example 15-16 Years, 17-23 Years ..... I have converted them to category and then cat.codes. However,the coding values start from 0 for the first group 0-4 years and I want the coding to start from 1 ie 0-4->1, 5-12-> and @@->NaN
      The suggested solution of using dictionary mapping still has issues. Following is mcve



      import pandas as pd
      data = ['0-4 Years', '5-12 Years','13-18 Years', '19-21 Years','22-25 Years','26-29 Years','30-35 Years',
      '36-41 Years','42-45 Years','46-49 Years','50-55 Years', '56-63 Years']
      df = pd.DataFrame(data,columns=['Age'],dtype=object)
      df['Age']=df['Age'].astype('category')
      cats = dict(enumerate(df['Age'].cat.categories, 2))
      df['Age']=df['Age'].cat.codes.map(cats).astype('category')
      df['Age']


      and here is the output, as you can see if I change the enumeration start other than 0, there is an issue with values as NaN. Secondly the column is not coded either:



      df['Age']
      0 NaN
      1 36-41 Years
      2 NaN
      3 NaN
      4 0-4 Years
      5 13-18 Years
      6 19-21 Years
      7 22-25 Years
      8 26-29 Years
      9 30-35 Years
      10 42-45 Years
      11 46-49 Years
      Name: Age, dtype: category
      Categories (9, object): [0-4 Years, 13-18 Years, 19-21 Years, 22-25 Years, ..., 30-35 Years, 36-41 Years, 42-45 Years, 46-49 Years]


      How to fix this.










      share|improve this question
















      I have object type columns that have categorical values example 15-16 Years, 17-23 Years ..... I have converted them to category and then cat.codes. However,the coding values start from 0 for the first group 0-4 years and I want the coding to start from 1 ie 0-4->1, 5-12-> and @@->NaN
      The suggested solution of using dictionary mapping still has issues. Following is mcve



      import pandas as pd
      data = ['0-4 Years', '5-12 Years','13-18 Years', '19-21 Years','22-25 Years','26-29 Years','30-35 Years',
      '36-41 Years','42-45 Years','46-49 Years','50-55 Years', '56-63 Years']
      df = pd.DataFrame(data,columns=['Age'],dtype=object)
      df['Age']=df['Age'].astype('category')
      cats = dict(enumerate(df['Age'].cat.categories, 2))
      df['Age']=df['Age'].cat.codes.map(cats).astype('category')
      df['Age']


      and here is the output, as you can see if I change the enumeration start other than 0, there is an issue with values as NaN. Secondly the column is not coded either:



      df['Age']
      0 NaN
      1 36-41 Years
      2 NaN
      3 NaN
      4 0-4 Years
      5 13-18 Years
      6 19-21 Years
      7 22-25 Years
      8 26-29 Years
      9 30-35 Years
      10 42-45 Years
      11 46-49 Years
      Name: Age, dtype: category
      Categories (9, object): [0-4 Years, 13-18 Years, 19-21 Years, 22-25 Years, ..., 30-35 Years, 36-41 Years, 42-45 Years, 46-49 Years]


      How to fix this.







      python mapping






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      edited Nov 22 '18 at 10:21







      aus_fas

















      asked Nov 22 '18 at 4:03









      aus_fasaus_fas

      207




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          1 Answer
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          0














          You can create you own dictionary that maps codes and categories with:



          cats = dict(enumerate(df['Age'].cat.categories, 1))


          And use this dictionary to map it in the dataframe



          df['Age'].cat.codes.map(cats).astype('category')





          share|improve this answer
























          • But what do you want to store in the column, the codes themselves?

            – b-fg
            Nov 22 '18 at 5:48











          • Also as I change the start of enumerate to any value higher than '1' then df['Age'] starts to have NaN for the categories where the mapping was available. The code upto cats is fine as I can see the categories based on dictionary but the second line seems to have an issue

            – aus_fas
            Nov 22 '18 at 6:08











          • The first line of code only creates a dictionary, so is not very useful on its own. That's why there a second line where you use the dictionary to map it to your dataframe.

            – b-fg
            Nov 22 '18 at 6:32











          • Maybe if you had provided a Minimum Complete and Verifiable Example this would not be the issue. So I encourage you to edit your question with some more content that other people can use to provide a better answer.

            – b-fg
            Nov 22 '18 at 6:43













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          1 Answer
          1






          active

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          active

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          active

          oldest

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          0














          You can create you own dictionary that maps codes and categories with:



          cats = dict(enumerate(df['Age'].cat.categories, 1))


          And use this dictionary to map it in the dataframe



          df['Age'].cat.codes.map(cats).astype('category')





          share|improve this answer
























          • But what do you want to store in the column, the codes themselves?

            – b-fg
            Nov 22 '18 at 5:48











          • Also as I change the start of enumerate to any value higher than '1' then df['Age'] starts to have NaN for the categories where the mapping was available. The code upto cats is fine as I can see the categories based on dictionary but the second line seems to have an issue

            – aus_fas
            Nov 22 '18 at 6:08











          • The first line of code only creates a dictionary, so is not very useful on its own. That's why there a second line where you use the dictionary to map it to your dataframe.

            – b-fg
            Nov 22 '18 at 6:32











          • Maybe if you had provided a Minimum Complete and Verifiable Example this would not be the issue. So I encourage you to edit your question with some more content that other people can use to provide a better answer.

            – b-fg
            Nov 22 '18 at 6:43


















          0














          You can create you own dictionary that maps codes and categories with:



          cats = dict(enumerate(df['Age'].cat.categories, 1))


          And use this dictionary to map it in the dataframe



          df['Age'].cat.codes.map(cats).astype('category')





          share|improve this answer
























          • But what do you want to store in the column, the codes themselves?

            – b-fg
            Nov 22 '18 at 5:48











          • Also as I change the start of enumerate to any value higher than '1' then df['Age'] starts to have NaN for the categories where the mapping was available. The code upto cats is fine as I can see the categories based on dictionary but the second line seems to have an issue

            – aus_fas
            Nov 22 '18 at 6:08











          • The first line of code only creates a dictionary, so is not very useful on its own. That's why there a second line where you use the dictionary to map it to your dataframe.

            – b-fg
            Nov 22 '18 at 6:32











          • Maybe if you had provided a Minimum Complete and Verifiable Example this would not be the issue. So I encourage you to edit your question with some more content that other people can use to provide a better answer.

            – b-fg
            Nov 22 '18 at 6:43
















          0












          0








          0







          You can create you own dictionary that maps codes and categories with:



          cats = dict(enumerate(df['Age'].cat.categories, 1))


          And use this dictionary to map it in the dataframe



          df['Age'].cat.codes.map(cats).astype('category')





          share|improve this answer













          You can create you own dictionary that maps codes and categories with:



          cats = dict(enumerate(df['Age'].cat.categories, 1))


          And use this dictionary to map it in the dataframe



          df['Age'].cat.codes.map(cats).astype('category')






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 22 '18 at 4:16









          b-fgb-fg

          1,96411422




          1,96411422













          • But what do you want to store in the column, the codes themselves?

            – b-fg
            Nov 22 '18 at 5:48











          • Also as I change the start of enumerate to any value higher than '1' then df['Age'] starts to have NaN for the categories where the mapping was available. The code upto cats is fine as I can see the categories based on dictionary but the second line seems to have an issue

            – aus_fas
            Nov 22 '18 at 6:08











          • The first line of code only creates a dictionary, so is not very useful on its own. That's why there a second line where you use the dictionary to map it to your dataframe.

            – b-fg
            Nov 22 '18 at 6:32











          • Maybe if you had provided a Minimum Complete and Verifiable Example this would not be the issue. So I encourage you to edit your question with some more content that other people can use to provide a better answer.

            – b-fg
            Nov 22 '18 at 6:43





















          • But what do you want to store in the column, the codes themselves?

            – b-fg
            Nov 22 '18 at 5:48











          • Also as I change the start of enumerate to any value higher than '1' then df['Age'] starts to have NaN for the categories where the mapping was available. The code upto cats is fine as I can see the categories based on dictionary but the second line seems to have an issue

            – aus_fas
            Nov 22 '18 at 6:08











          • The first line of code only creates a dictionary, so is not very useful on its own. That's why there a second line where you use the dictionary to map it to your dataframe.

            – b-fg
            Nov 22 '18 at 6:32











          • Maybe if you had provided a Minimum Complete and Verifiable Example this would not be the issue. So I encourage you to edit your question with some more content that other people can use to provide a better answer.

            – b-fg
            Nov 22 '18 at 6:43



















          But what do you want to store in the column, the codes themselves?

          – b-fg
          Nov 22 '18 at 5:48





          But what do you want to store in the column, the codes themselves?

          – b-fg
          Nov 22 '18 at 5:48













          Also as I change the start of enumerate to any value higher than '1' then df['Age'] starts to have NaN for the categories where the mapping was available. The code upto cats is fine as I can see the categories based on dictionary but the second line seems to have an issue

          – aus_fas
          Nov 22 '18 at 6:08





          Also as I change the start of enumerate to any value higher than '1' then df['Age'] starts to have NaN for the categories where the mapping was available. The code upto cats is fine as I can see the categories based on dictionary but the second line seems to have an issue

          – aus_fas
          Nov 22 '18 at 6:08













          The first line of code only creates a dictionary, so is not very useful on its own. That's why there a second line where you use the dictionary to map it to your dataframe.

          – b-fg
          Nov 22 '18 at 6:32





          The first line of code only creates a dictionary, so is not very useful on its own. That's why there a second line where you use the dictionary to map it to your dataframe.

          – b-fg
          Nov 22 '18 at 6:32













          Maybe if you had provided a Minimum Complete and Verifiable Example this would not be the issue. So I encourage you to edit your question with some more content that other people can use to provide a better answer.

          – b-fg
          Nov 22 '18 at 6:43







          Maybe if you had provided a Minimum Complete and Verifiable Example this would not be the issue. So I encourage you to edit your question with some more content that other people can use to provide a better answer.

          – b-fg
          Nov 22 '18 at 6:43




















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