I\'ve created a Pandas DataFrame
df = DataFrame(index=[\'A\',\'B\',\'C\'], columns=[\'x\',\'y\'])
and got this
x y A NaN
If you want to change values not for whole row, but only for some columns:
x = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]}) x.iloc[1] = dict(A=10, B=-10)