CODE EXAMPLE FOR PYTHON

Normalize columns in pandas dataframe

In [5]: %paste                                                                                                                                                                                                                                                                       
cols = ['2002', '2003', '2004', '2005']
df[cols] = df[cols] / df[cols].sum()

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In [6]: df                                                                                                                                                                                                                                                                           
Out[6]: 
      term      2002      2003      2004      2005
0  climate  0.043478  0.454545  0.333333  0.466667
1   global  0.521739  0.500000  0.666667  0.400000
2  nuclear  0.434783  0.045455  0.000000  0.133333