python核心编程-练习2

1.测试字母，数字，下划线：

#!usr/bin/env pythonimport stringalphas = string.letters + '_'print alphasnums = string.digitsprint numsprint '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" % myInputif 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：

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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>

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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>