Answers for "python dataframe how to turn all ? into null"

how to replace null values in pandas

df['DataFrame Column'] = df['DataFrame Column'].fillna(0)

pandas nat to null?

dfTest2['InvoiceDate'] = (dfTest2['InvoiceDate']
                          .astype(str) # <- cast to string to simplify
                                       #    .replace() in newer versions
                          .replace({'NaT': None} # <- replace with None
                         )