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! :) -- http://mail.python.org/mailman/listinfo/python-list