Question asked earlier today -- but this should be legible and understandable. Everything is outputted to "MQ_List-output.csv"

csvtest.py

#!/usr/bin/env python
import csv
import sys
import os.path

#filename1 = csv with all the important rows (inputfile)
#filename2 = csv that sorts filename1 by groups (sortby)
#filename3 = alternate filename, by default it is filename1 appended with '-output.csv' (output_file)

if len(sys.argv) <= 2:
    print "usage: %s inputfile sortbyfile [outputfile]" % sys.argv[0]
    sys.exit(0)

filename1 = sys.argv[1]
filename2 = sys.argv[2]

try:
    filename3 = sys.argv[3]
except IndexError:
    basename, ext = os.path.splitext(filename1)
    filename3 = "%s-output.csv" % basename

inputfile = open(filename1)
sortby = open(filename2)
outputfile = open(filename3, "w")

mq_list = [row for row in csv.reader(inputfile)]
themap = [row for row in csv.reader(sortby)]
output = csv.writer(outputfile)

map_lookup = {}
grouped_by = {}

for symbol,group in themap:
    map_lookup[ symbol ] = group
    grouped_by[ group ] = []

for row in mq_list:
    try:
        grouped_by[ map_lookup[ row[0] ] ] += [row]
    except KeyError:
        print "couldn't find group of %s" % row[0]

for k in sorted(grouped_by.keys()):
    for row in grouped_by[k]:
        output.writerow(row)

inputfile.close()
sortby.close()
outputfile.close()