Something

#! /usr/bin/env python# Given address book CSV data with display name values in the format of# "Firstname Lastname", change to "Lastname, Firstname".import csv, StringIOdata = '''"First Name","Last Name","Display Name""James","Kirk","James Kirk""Spock","","Spock""Leonard","McCoy","Leonard McCoy"'''inf = ('First Name','Last Name','Display Name')i = StringIO.StringIO(data)r = csv.DictReader(i, inf)o = StringIO.StringIO()w = csv.DictWriter(o, inf)def main():	for row in r:		if row['Display Name'] == 'Display Name':			pass		else:			if len(row['Last Name']) > 0:				s = '%s, %s' % (row['Last Name'], row['First Name'])				row['Display Name'] = s		w.writerow(row)	print o.getvalue()if __name__ == '__main__':	main()