Add Columns To Pandas Dataframe Containing Max Of Each Row, And Corresponding Column Name

My system Windows 7, 64 bit python 3.5.1 The challenge I've got a pandas dataframe, and I would like to know the maximum value for each row, and append that info as a new column. I

Solution 1:

You can compare the df against maxval using eq with axis=0, then use apply with a lambda to produce a boolean mask to mask the columns and join them:

In [183]:
df['maxcol'] = df.ix[:,:'c'].eq(df['maxval'], axis=0).apply(lambda x: ','.join(df.columns[:3][x==x.max()]),axis=1)
df

Out[183]:
   a  b  c  maxval maxcol
0  1  0  0       1      a
1  0  0  0       0  a,b,c
2  0  1  0       1      b
3  1  0  0       1      a
4  3  1  0       3      a