finding dupes (with a twist)

[buran]

It's not working because you try to refer another DataFrame columns.

Output:
Division,field2,field3,field4,Email
Electrical,field2,field3,field4,[email protected]
Automotive,field2,field3,field4,[email protected]
Fuses,field2,field3,field4,[email protected]
Electrical,field2,field3,field4,[email protected]
Automotive,field2,field3,field4,[email protected]
Fuses,field2,field3,field4,[email protected]
Electrical,field2,field3,field4,[email protected]
Automotive,field2,field3,field4,[email protected]
Fuses,field2,field3,field4,[email protected]

import pandas as pd 
 
df = pd.read_csv('Tdf contacts.csv')
df['Email'] = df['Email'].apply(lambda x: x.lower())
df.drop_duplicates(subset=['Division', 'Email'], keep=False).to_csv('dupes_cleaned.csv', index=False)

cleaned:

Output:
Division,field2,field3,field4,Email
Automotive,field2,field3,field4,[email protected]
Automotive,field2,field3,field4,[email protected]
Electrical,field2,field3,field4,[email protected]
Automotive,field2,field3,field4,[email protected]
Fuses,field2,field3,field4,[email protected]