问题
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!
回答1:
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)
来源：https://stackoverflow.com/questions/23208745/adding-dummy-columns-to-the-original-dataframe