Change an element in the last row of a DataFrame

Question

I set up a simple DataFrame in pandas:

a = pandas.DataFrame([[1,2,3], [4,5,6], [7,8,9]], columns=[\'a\',\'b\',\'c\'])
>>> print a
   a  b  c
0  1  2         


        

Answer 1

Taking elements from the solutions of @PallavBakshi and @Mike, the following works in Pandas >= 0.19

Just using iloc[-1, 'a] won't work as -1 is not in the index.

a.loc[a.index[-1], 'a']= 4.0