drop_duplicates not working in pandas?

Question

The purpose of my code is to import 2 Excel files, compare them, and print out the differences to a new Excel file.

However, after concatenating all the data, and us

Answer 1

You've got inplace=False so you're not modifying df. You want either

 df.drop_duplicates(subset=None, keep="first", inplace=True)

or

 df = df.drop_duplicates(subset=None, keep="first", inplace=False)