I\'ve created a Pandas DataFrame
df = DataFrame(index=[\'A\',\'B\',\'C\'], columns=[\'x\',\'y\'])
and got this
x y A NaN
Soo, your question to convert NaN at ['x',C] to value 10
the answer is..
df['x'].loc['C':]=10 df
alternative code is
df.loc['C':'x']=10 df