csvdiff

#!/usr/bin/env python2.7
# Copyright (C) Punyashloka Biswal <punya.biswal@gmail.com> 2011

from __future__ import print_function
import argparse, csv

parser = argparse.ArgumentParser(
    description='find significant differences between CSV files',
    formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument(
    'inputs', help='input CSV file',  metavar='<INPUT.CSV>', nargs='+',
    type=lambda filename:
        dict(((row[1], row[2]), float(row[3]))
             for row in csv.reader(argparse.FileType('rU')(filename))
             if row[1] != '' and row[2] != ''))
parser.add_argument(
    '--out', help='output CSV file', metavar='<OUTPUT.CSV>',
    type=lambda string: csv.writer(argparse.FileType('wb')(string)))
parser.add_argument(
    '--lower', type=float, default=-0.45, help='negative significant limit')
parser.add_argument(
    '--upper', type=float, default=0.45,  help='positive significant limit')

args = parser.parse_args()

def sig(num):
    if num is None:
        return ''
    elif num < args.lower:
        return '-'
    elif num > args.upper:
        return '+'
    else:
        return '?'

args.out.writerows(
    list(key) + [sig(inp.get(key, None))
                 for inp in args.inputs]
    for key in set().union(*[inp.keys()
                             for inp in args.inputs]))