python_判断标识符的合法性

利用keyword模块中的kwlist排除了关键字

#!/usr/bin/env python
# -*- coding:utf-8 -*-

'''
@File  : stringPractice.py
@Author: Grace
@Date  : 2018/7/30
@Desc  : 字符串相关的例题实现
'''

# import modules
import string
import keyword

# function definition
def idChecher(idstr):
    '检查标识符是否符合规则，比较简单，没有排除关键字'
    alphas = string.letters+'_'
    nums = string.digits
    length = len(idstr)
    alphanum = alphas+nums

    if idstr[0] not in alphas:
        print 'invalid: the first symbol must be a letter or _'
        return False
    if length>1:
        if idstr in keyword.kwlist:
            print 'invalid: symbol cannot be a keyword'
            return False
        for otherchar in idstr[1:]:
            if otherchar not in alphanum:
                print 'invalid: other symbols must be numbers, letters, or _'
                return False
        return True
    else:
        return True


# main function
if __name__ == '__main__':
    pass