Help me with the script? How to find items in csv file A and not in file B and vice versa

[Alan Newbie]

Hello,
Let's say I want to compare two csv files: file A and file B. They are both similarly built - the first column has product IDs (one product per row) and the columns provide some stats about the products such as sales in # and $.

I want to compare these files - see which product IDs appear in the first column of file A and not in B, and which in B and not A.
Finally, it would be very great if the result could be written into two new CSV files - one product ID per row in the first column. (no other data in the other columns needed)

This is the script I tried:
==========================

import csv

#open CSV's and read first column with product IDs into variables pointing to lists
A = [line.split(',')[0] for line in open('Afile.csv')]
B = [line.split(',')[0] for line in open('Bfile.csv')]

#create variables pointing to lists with unique product IDs in A and B respectively 
inAnotB = list(set(A)-set(B))
inBnotA = list(set(B)-set(A))

print inAnotB
print inBnotA

c = csv.writer(open("inAnotB.csv", "wb"))
c.writerow([inAnotB])


d = csv.writer(open("inBnotA.csv", "wb"))
d.writerow([inBnotA])

print "done!" 

=====================================================

But it doesn't produce the required results.
It prints IDs in this format:
247158132\n

and nothing to the csv files.

You could probably tell I'm a newbie.
Could you help me out?

here's some dummy data:
https://docs.google.com/file/d/0BwziqsHUZOWRYU15aEFuWm9fajA/edit?usp=sharing

https://docs.google.com/file/d/0BwziqsHUZOWRQVlTelVveEhsMm8/edit?usp=sharing

Thanks a bunch in advance! :)