mean

#!/usr/bin/env python

import os
import sys
import argparse

arg_parser = argparse.ArgumentParser()
arg_parser.add_argument('-p', dest='precision', type=int, default=5, help='number of decimal points')
arg_parser.add_argument('-i', dest='index', type=int, default=0, help='column index to use')
arg_parser.add_argument('-v', action="store_true", default=False, help='be verbose')
args = arg_parser.parse_args()

total = 0.0
i = 0
for i, line in enumerate(sys.stdin):
    total += float(line.rstrip().split()[args.index])

divisor = 1.0
if os.path.basename(sys.argv[0]) == 'mean':
    divisor = i + 1

if args.v:
    formatstr = "%%.%df / %d = %%.%df" % (args.precision, i + 1, args.precision)
    print(formatstr % (total, total / (i + 1)))
else:
    formatstr = "%%.%df" % args.precision
    print(formatstr % (total / (i + 1)))