#!/usr/bin/env python

# Subtracts map spreadsheet A1->C from A0->B to A->B

import csv

import sys

def main():

    try: _prog_name, map_1_path = sys.argv

    except ValueError:

        raise SystemExit('Usage: '+sys.argv[0]+' <map_0 map_1 [| '+sys.argv[0]

            +' map_2]... >subtraction_map')

    # Get map 1

    map_1 = {}

    stream = open(map_1_path, 'rb')

    reader = csv.reader(stream)

    map_1_cols = reader.next()

    for row in reader:

        if row[0] != '': map_1[row[0]] = row

    stream.close()

    # Open map 0

    reader = csv.reader(sys.stdin)

    map_0_cols = reader.next()

    if map_0_cols[0] != map_1_cols[0]: raise SystemExit('Map error: '

        'Map 1 column 0 name doesn\'t match map 0 column 0 name')

    # Subtract map 1 from map 0

    writer = csv.writer(sys.stdout)

    writer.writerow(map_0_cols)

    for row in reader:

        if row[0] not in map_1: writer.writerow(row)

main()