python核心编程-练习2

1.测试字母，数字，下划线：

#!usr/bin/env python

import string

alphas = string.letters + '_'
print alphas
nums = string.digits
print nums

print 'Welcome to the Identifier Checker v1.0'
print 'Testees must be at least 2 chars long.'
myInput = raw_input('Identifier to test? ')

print "you input :-> %s \n" % myInput
if len(myInput) > 1:
if myInput[0] not in alphas:
print '''invalid: first symbol must be alphabetic'''
else:
for otherChar in myInput[1:]:
print 'for----->%s\n' % otherChar
if otherChar not in alphas + nums:
print '''invalid: remaining symbols must be alphanumeric'''
break
else:
print "okay as an identifier"

测试结果：

测试情况2：

D:\Python27\test>letter.py

abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_

0123456789

Welcome to the Identifier Checker v1.0

Testees must be at least 2 chars long.

Identifier to test? 3hello（输入）

you input :-> 3hello

invalid: first symbol must be alphabetic

D:\Python27\test>

测试情况2：

D:\Python27\test>letter.py

abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_

0123456789

Welcome to the Identifier Checker v1.0

Testees must be at least 2 chars long.

Identifier to test? hellooo（输入）

you input :-> hellooo

for—–>e

for—–>l

for—–>l

for—–>o

for—–>o

for—–>o

okay as an identifier

D:\Python27\test>