string

#!/usr/bin/env python
import string
alphas = string.letters + '_'
nums = string.digits
print 'Welcome to the Identifier Checker v1.0'
print 'Testees must be at least 2 chars long.'
myInput = raw_input('Identifier to test? ')
if len(myInput) > 1:
   if myInput[0] not in alphas:
       print '''invalid: first symbol must be alphabetic'''
   else:
       for otherChar in myInput[1:]:
           if otherChar not in alphas + nums:
               print '''invalid: remaining symbols must be alphanumeric'''
               break
           else:
               print "okay as an identifier", otherChar

[root@localhost tmp]# ./2
Welcome to the Identifier Checker v1.0
Testees must be at least 2 chars long.
Identifier to test? inihao
okay as an identifier n
okay as an identifier i
okay as an identifier h
okay as an identifier a
okay as an identifier o

>>> import string
>>> alphas = string.letters + '_'
>>> alphas
'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_'

>>> nums = string.digits
>>> nums
'0123456789'