From a DataFrame how do I get the column name for the column that has the max value

Question

If I have a DataFrame with numeric values in it, how do I determine which column contains the max value?

	EEM_X	EFA_X	QQQ_X	SPY_X
126	0.1898	0.1490	0.1025	0.0965
127	0.1911	0.1476	0.0678	0.0793
128	0.1986	0.1590	0.0750	0.0893
129	0.2180	0.1703	0.0783	0.0924

I want to add a new column ['MAX'] that contains the column name where the value in each row is the highest.

Answer 1

This shoud work:

df.apply(pd.Series.idxmax, axis=1)