Outputs a simple average of all numbers, or given a size of numbers to group, will output a running average.

runavg.py

#!/usr/bin/env python

"""$ c=1;while true;do echo $c;let c=$c+1;sleep .5;done | ./avg.py -n 10
5.5
15.5
25.5
..."""

#Copyright 2005 Drew Gulino
##This program is free software; you can redistribute it and/or modify
##    it under the terms of the GNU General Public License as published by
##    the Free Software Foundation; either version 2 of the License, or
##    (at your option) any later version.
##
##    This program is distributed in the hope that it will be useful,
##    but WITHOUT ANY WARRANTY; without even the implied warranty of
##    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
##    GNU General Public License for more details.
##
##    You should have received a copy of the GNU General Public License
##    along with this program; if not, write to the Free Software
##    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA



import sys, os, getopt
from getopt import GetoptError

class Avg:

    def __init__(self,avg_width,digits,avg_all):
        self.avg_width = avg_width
        self.total = 0
        self.count = 0
        self.digits = digits
        self.avg_all = avg_all

    def readLine(self,fileObj):
        bytes = []
        while True:
            try:
                b = fileObj.read()
            except IOError, e:
                if e.args[0] == sys.errno.EAGAIN:
                    break
                raise
            except KeyboardInterrupt:
                break
            bytes.append(b)
            if b == chr(10) or b == chr(13):
#                bytes.append(chr(10))
                break
            if b == chr(3):
                sys.exit()
        return ''.join(bytes)

    def nonBlockingReadAll(self,fileObj):
            bytes = []
            while True:
                try:
                    b = fileObj.read(1024)
                except IOError, e:
                    if e.args[0] == sys.errno.EAGAIN:
                        break
                    raise
                bytes.append(b)
                if len(b) < 1024:
                    break
            return ''.join(bytes)

def usage(progname):
    print "usage: " + progname
    version()
    print "[-h --help]"
    print "[-v --version]"
    print "[-n --nums_to_avg] Size of number groups to average (default=all)"
    print "[-d --digits] Significant digits to display (default=all)"

def version():
    print "version: 1.0.1"


def main(argv, stdout, environ):
    avg_width = 0
    digits = 0
    avg_all = 1

    progname = argv[0]
    try:
        arglist, args = getopt.getopt(argv[1:], "hvn:d:", ["help", "version", "nums_to_avg=", "digits="])
    except GetoptError:
        print "Invalid Option!"
        usage(progname)
        return

    # Parse command line arguments
    for (field, val) in arglist:
        if field in ("-h", "--help"):
            usage(progname)
            return
        if field in ("-v", "--version"):
            version()
            return
        if field in ("-n", "--nums_to_avg"):
            avg_width = int(val)
            avg_all = 0
        if field in ("-d", "--digits"):
            digits = int(val)

    avg = Avg(avg_width,digits,avg_all)
    while 1:
#        number = sys.input()
#        number = sys.nonBlockingReadAll(sys.stdin)
#        number = avg.readLine(sys.stdin)
        try:
            number = sys.stdin.readline()
            if not number:
                break
            number = float(number)
            if avg.avg_all == 1:
                avg.total += number
                avg.count += 1
                avg.avg_width += 1
            else:
                avg.count += 1
                avg.total += number
                if avg.count < avg.avg_width:
                    pass
                else:
                    number = avg.total / avg.count
                    if digits > 0:
                        number = round(number,digits)
                    sys.stdout.write(str(number))
                    sys.stdout.write("\n")
                    sys.stdout.flush()
                    avg.total = 0
                    avg.count = 0
        except(ValueError):
            sys.stdout.write("Number Value Exception\n")
            sys.stdout.flush()
    if avg.avg_all == 1:
        number = avg.total / avg.count
        if digits > 0:
            number = round(number,digits)
        sys.stdout.write(str(number))
        sys.stdout.write("\n")
        sys.stdout.flush()

if __name__ == "__main__":
    main(sys.argv, sys.stdout, os.environ)