python 字符串实例：检查并判断密码字符串的安全强度

import string
def check(pwd):
    #密码必须至少包含六个字符
    if not isinstance(pwd,str) or len(pwd)<6:
        return ‘noot suitable for password‘
    #密码强度等级与包含字符种类的对应关系
    d = {1:‘weak‘,2:‘below middle‘,3:‘above middle‘,4:‘strong‘}
    #分别用来标记pwd是否含有数字、小写字母、大写字母、指定的标点符号
    r = [False]*4
    pwd_range = string.ascii_uppercase+string.ascii_lowercase+string.digits+‘,.!;><?‘

    for ch in pwd:
        if ch not in pwd_range:
            return ‘error‘
        elif not r[0] and ch in string.digits:
            r[0] = True
        elif not r[1] and ch in string.ascii_lowercase:
            r[1] = True
        elif not r[2] and ch in string.ascii_uppercase:
            r[2] = True
        elif not r[3] and ch in ‘,.!;?<>‘:
            r[3] = True

    #统计包含的字符种类，返回密码强度
    return d.get(r.count(True),‘error‘)

def program():
    while True:
        pwd = input("请输入您的密码：")
        print(check(pwd))

program()