adding dummy columns to the original dataframe

python pandas dataframe one-hot-encoding

41,886

In [77]: df = pd.concat([df, pd.get_dummies(df['YEAR'])], axis=1); df
Out[77]: 
      JOINED_CO GENDER    EXEC_FULLNAME  GVKEY  YEAR    CONAME  BECAMECEO  \
5622        NaN   MALE   Ira A. Eichner   1004  1992  AAR CORP   19550101   
5622        NaN   MALE   Ira A. Eichner   1004  1993  AAR CORP   19550101   
5622        NaN   MALE   Ira A. Eichner   1004  1994  AAR CORP   19550101   
5622        NaN   MALE   Ira A. Eichner   1004  1995  AAR CORP   19550101   
5622        NaN   MALE   Ira A. Eichner   1004  1996  AAR CORP   19550101   
5622        NaN   MALE   Ira A. Eichner   1004  1997  AAR CORP   19550101   
5622        NaN   MALE   Ira A. Eichner   1004  1998  AAR CORP   19550101   
5623        NaN   MALE  David P. Storch   1004  1992  AAR CORP   19961009   
5623        NaN   MALE  David P. Storch   1004  1993  AAR CORP   19961009   
5623        NaN   MALE  David P. Storch   1004  1994  AAR CORP   19961009   
5623        NaN   MALE  David P. Storch   1004  1995  AAR CORP   19961009   
5623        NaN   MALE  David P. Storch   1004  1996  AAR CORP   19961009   

      REJOIN   LEFTOFC    LEFTCO  RELEFT    REASON  PAGE  1992  1993  1994  \
5622     NaN  19961001  19990531     NaN  RESIGNED    79     1     0     0   
5622     NaN  19961001  19990531     NaN  RESIGNED    79     0     1     0   
5622     NaN  19961001  19990531     NaN  RESIGNED    79     0     0     1   
5622     NaN  19961001  19990531     NaN  RESIGNED    79     0     0     0   
5622     NaN  19961001  19990531     NaN  RESIGNED    79     0     0     0   
5622     NaN  19961001  19990531     NaN  RESIGNED    79     0     0     0   
5622     NaN  19961001  19990531     NaN  RESIGNED    79     0     0     0   
5623     NaN       NaN       NaN     NaN       NaN    57     1     0     0   
5623     NaN       NaN       NaN     NaN       NaN    57     0     1     0   
5623     NaN       NaN       NaN     NaN       NaN    57     0     0     1   
5623     NaN       NaN       NaN     NaN       NaN    57     0     0     0   
5623     NaN       NaN       NaN     NaN       NaN    57     0     0     0   

      1995  1996  1997  1998  
5622     0     0     0     0  
5622     0     0     0     0  
5622     0     0     0     0  
5622     1     0     0     0  
5622     0     1     0     0  
5622     0     0     1     0  
5622     0     0     0     1  
5623     0     0     0     0  
5623     0     0     0     0  
5623     0     0     0     0  
5623     1     0     0     0  
5623     0     1     0     0

If you'd like to delete the YEAR column, then you could follow this up with del df['YEAR']. Or, drop the YEAR column from df before calling concat:

df = pd.concat([df.drop('YEAR', axis=1), pd.get_dummies(df['YEAR'])], axis=1)

41,886

Author by

Brad

Updated on July 21, 2022

Comments

Brad almost 2 years

I have a dataframe looks like this:

             JOINED_CO GENDER    EXEC_FULLNAME  GVKEY  YEAR  CONAME  BECAMECEO  REJOIN   LEFTOFC    LEFTCO  RELEFT    REASON  PAGE
CO_PER_ROL                                                                                                                                     
5622              NaN   MALE   Ira A. Eichner   1004  1992  AAR CORP   19550101     NaN  19961001  19990531     NaN  RESIGNED    79
5622              NaN   MALE   Ira A. Eichner   1004  1993  AAR CORP   19550101     NaN  19961001  19990531     NaN  RESIGNED    79
5622              NaN   MALE   Ira A. Eichner   1004  1994  AAR CORP   19550101     NaN  19961001  19990531     NaN  RESIGNED    79
5622              NaN   MALE   Ira A. Eichner   1004  1995  AAR CORP   19550101     NaN  19961001  19990531     NaN  RESIGNED    79
5622              NaN   MALE   Ira A. Eichner   1004  1996  AAR CORP   19550101     NaN  19961001  19990531     NaN  RESIGNED    79
5622              NaN   MALE   Ira A. Eichner   1004  1997  AAR CORP   19550101     NaN  19961001  19990531     NaN  RESIGNED    79
5622              NaN   MALE   Ira A. Eichner   1004  1998  AAR CORP   19550101     NaN  19961001  19990531     NaN  RESIGNED    79
5623              NaN   MALE  David P. Storch   1004  1992  AAR CORP   19961009     NaN       NaN       NaN     NaN       NaN    57
5623              NaN   MALE  David P. Storch   1004  1993  AAR CORP   19961009     NaN       NaN       NaN     NaN       NaN    57
5623              NaN   MALE  David P. Storch   1004  1994  AAR CORP   19961009     NaN       NaN       NaN     NaN       NaN    57
5623              NaN   MALE  David P. Storch   1004  1995  AAR CORP   19961009     NaN       NaN       NaN     NaN       NaN    57
5623              NaN   MALE  David P. Storch   1004  1996  AAR CORP   19961009     NaN       NaN       NaN     NaN       NaN    57

For the YEAR value, I like to add year columns (1993,1994...,2009) to the original dataframe, If the value in YEAR is 1992, then the value in the 1992 column should be 1 otherwise 0.

I used a very stupid for loop, but it seems to run forever as I have a large dataset. Could anyone help me with it, thanks a lot!

guo over 7 years

what doesin [77] mean?
unutbu over 7 years

@guo: That is IPython's interactive shell prompt. It numbers the inputs.
Nihat almost 4 years

why am I doubling my original frame with this code block? any guesses? @unutbu