rocks.py

import csv
import itertools
l = list(csv.DictReader(open('Mailchimp_GeoTwitter.csv')))


col_email = 'Email Address'
col_address = 'Your Mailing Address (where you receive your rock)'
col_shipping = 'Are you willing to ship internationally?'
col_first_name = 'First Name'
col_last_name = 'Last Name'
col_rock_type = "Any rock type you'd like to add to your collection"
col_twitter_handle = 'Your twitter handle (optional)'
is_international = {'No, I do not want to ship internationally': False, 'Yes, but I prefer domestic': False, 'Yes, I prefer international': True }

nl = [(e[col_email], e[col_address].split(' ')[-1], is_international[e[col_shipping]]) for e in l if e [col_address] != '']

for_email = dict((e[col_email], e) for e in l)


nnl = [('international' if e[2] else e[1], e[0]) for e in nl]

grouped = [list(e[1] for e in j[1]) for j in itertools.groupby(sorted(nnl), lambda e: e[0])]

def loop(l): return list(zip(l, l[1:] + [l[0]]))

email_match = list(itertools.chain(*[loop(e) for e in grouped]))

def gen():
    for src, dest in email_match:
        d = dict(for_email[dest])
        yield {
            "Gifter": src,
            "Giftee": dest,
            "Giftee's First Name": d[col_first_name],
            "Giftee's Last Name": d[col_last_name],
            "Giftee's Twitter Handle": d[col_twitter_handle],
            "Giftee's Address": d[col_address],
            "Giftee's Rock Preference": d[col_rock_type]
        }

ol = list(gen())
with open('out.csv', 'w') as fo:
    writer = csv.DictWriter(fo, ol[0].keys())
    writer.writeheader()
    for row in ol:
        writer.writerow(row)