fbcrosssection.py

#!/usr/bin/python
"""
Compare two small csv files and create two new files, one with matches, the other which don't match.

I use it here to to get the names and email addresses from "personal" FB friends which are in a specific group.
It loops the group and pulls matches from the friends list, so that only group members whom are also found in the 
friends list will be included in the GroupFriends list.

A hipper, more efficient approach is found here: https://stackoverflow.com/a/23090697/2223106
"""

import csv

f1 = file('FBGroupMembers.csv', 'r')
f2 = file('FBFriends.csv', 'r')
f3 = file('GroupFriends.csv', 'w')
f4 = file('GroupNonFriends.csv', 'w')

group_reader = csv.reader(f1)
friends_reader = csv.reader(f2)
crosssection_writer = csv.writer(f3)
non_match_writer = csv.writer(f4)

friend_list = list(friends_reader)

for group_row in group_reader:
	row = 1
	found = False
	for friends_row in friend_list:
		results_row = group_row
		if friends_row[0].lower() == group_row[1].lower() or friends_row[3].lower() == group_row[2].lower():
			friends_row[0] = friends_row[0].title()
			friends_row[3] = friends_row[3].title()
			print(friends_row[0] +'\t'+friends_row[3]+' found.')
			crosssection_writer.writerow(friends_row)
			found = True
			break
		row = row + 1
	if not found:
		results_row.append('NOT FOUND in master list')
		non_match_writer.writerow(group_row)

f1.close()
f2.close()
f3.close()
f4.close()