Question

I have a csv file like this :

column1    column2

john       kerry
adam       stephenson
ashley     hudson
john       kerry
etc..

I want to remove duplicates from this file, to get only :

column1    column2

john       kerry
adam       stephenson
ashley     hudson

I wrote this script that removes duplicates based on lastnames, but I need to remove duplicates based on lastnames AND firstname.

import csv

reader=csv.reader(open('myfilewithduplicates.csv', 'r'), delimiter=',')
writer=csv.writer(open('myfilewithoutduplicates.csv', 'w'), delimiter=',')

lastnames = set()
for row in reader:
    if row[1] not in lastnames:
        writer.writerow(row)
        lastnames.add( row[1] )

Answer 1

You’re really close. Use those columns as the set entry

entries = set()

for row in reader:
   key = (row[0], row[1]) # instead of just the last name

   if key not in entries:
      writer.writerow(row)
      entries.add(key)