The code it down to 5 lines! #!/usr/bin/python
barred = set(open('/home/sajid/python/wip/CBR0000319.dat')) postpaid_file = open('/home/sajid/python/wip/PSP0000320.dat') outfile = open('/home/sajid/python/wip/PSP-CBR.dat', 'w') outfile.writelines(number for number in postpaid_file if number not in barred) postpaid_file.close(); outfile.close() Awesome! (-: Thanks a ton Fredrik, Steve. $ time ./cleanup.py real 0m11.048s user 0m5.232s sys 0m0.584s But there seem to be that discrepancy; will chk and update back here. Thank you all once again. -- http://mail.python.org/mailman/listinfo/python-list