fh.py

#!/usr/bin/env python2
try:
    year_input = int(raw_input('Please enter a 4-digit year: '))
except:
    exit('1st arg must be 4-digit year between 1926 and 2012')

factor_input = raw_input('please enter a Fama-French factor:  ')

mylist = []
with open('F-F_Research_Data_Factors_daily.txt') as fh:
    lines = fh.readlines()
    slicedline = lines[6:-2]
    header = lines[5].split()

    if year_input >= 1926 and year_input <= 2012:
        print 'available factors: {0}'.format(header)  
    else:
        exit('1st arg must be 4-digit year between 1926 and 2012')

    for element in slicedline:
        factor_index = header.index(factor_input) + 1
        if year_input == int(element.split()[0][:4]):
            value = element.split()[factor_index]
            mylist.append(value)

    if factor_input in header:
        len_list = len(mylist)
        sumlist = sum([float(y) for y in mylist])
        print '{0} values, avg {1}'.format(len_list,sumlist/len_list)
    else:
         print '2nd arg must be one of the four factors {0}'. format(header)