How to replace a value in pandas, with NaN?

Question

I am new to pandas , I am trying to load the csv in Dataframe. My data has missing values represented as ? , and I am trying to replace it with standard Missing values - NaN

Answer 1

okay I got it by :

 #========trying to replace ?
    newraw= rawfile.replace('[?]', np.nan, regex=True)
    print newraw[25:40]