Age, Workclass, Fnlwgt, Education, Educationnum, Maritalstatus, Occupation, Relationship, Race, Sex, Capitalgain, Capitalloss, Hoursperweek, Nativecountry, Class

f = open('t', 'w')
for line in open('train.csv'):
    line = line[:-1].split(',')
    if len(line) < 1:
            continue
    if line[0] == '?':
            line = ','.join(line)
            print line
    age = int(line[0])
    if age in range(25): age = '0025'
    if age in range(25, 40): age = '2639'
    if age in range(40, 60): age = '4059'
    if age in range(60, 80): age = '6080'
    if age in range(80, 120): age = '8080'
    line[0] = age
    line = ','.join(line)
    f.write(line+'\n')