Replace None with NaN in pandas dataframe

Question

I have table x:

        website
0   http://www.google.com/
1   http://www.yahoo.com
2   None

I want to replace python None with pa

Answer 1

If you use df.replace([None], np.nan, inplace=True), this changed all datetime objects with missing data to object dtypes. So now you may have broken queries unless you change them back to datetime which can be taxing depending on the size of your data.

If you want to use this method, you can first identify the object dtype fields in your df and then replace the None:

obj_columns = list(df.select_dtypes(include=['object']).columns.values)
df[obj_columns] = df[obj_columns].replace([None], np.nan)