Question

我有一个用Python制造的Discord机器人，用于查找用户名。用户名只能是A-z和0-9。如何阻止人们使用特殊符号进行查询？

不允许的示例：

robotic@934!@

允许的示例：

Anf
GGDFG94

由于人们可以查找任何名称，所以只允许某些字符而不是完整的单词/单词的一部分将是有益的。

whitelist = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0']

if SOMETHINGTOCOMPARE in whitelist:
    print("You are allowed to look this username up.")
else:
    print("Your username contains special characters. Disallowed.")

我将用户名存储在“响应”字符串中

Answer 1

如果只想允许使用字母和数字，那么您所需要的只是str.isalnum方法（“数字”代表“字母数字”）：

if SOMETHINGTOCOMPARE.isalnum():
    ...

否则，其他答案中有几个选项。我个人将使用all：

from string import digits, ascii_letters

whitelist = set(digits + ascii_letters + "#_-[]")

if all(c in whitelist for c in SOMETHINGTOCOMPARE):
    ...

Answer 2

您只想检查一个集合中的字符，而不是其他集合中的字符，因此从根本上讲，您应该查看设置操作。

https://docs.python.org/3.8/library/stdtypes.html#set-types-set-frozenset

import string

def acceptable(querystring):
    acceptable = set(string.ascii_letters + string.digits)
    guess = set(querystring)
    disallowed_characters_in_guess = guess - acceptable
    return not bool(disallowed_characters_in_guess)
    
if acceptable("robotic@934!@"):
    raise ValueError

if not acceptable("robotic934"):
    raise ValueError

print ("okay")

Answer 3

您可以检查SOMETHINGTOCOMPARE是否是whitelist（set）的子集：

def check(SOMETHINGTOCOMPARE):
    whitelist = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0']

    # Test whether every element in SOMETHINGTOCOMPARE is in whitelist.
    if set(SOMETHINGTOCOMPARE) <= set(whitelist):
        return True
    return False

您可以使用以下方法测试该功能：

if check('robotic@934!@'):
    print("You are allowed to look this username up.")
else:
    print("Your username contains special characters. Disallowed.")

if check('Anf'):
    print("You are allowed to look this username up.")
else:
    print("Your username contains special characters. Disallowed.")

if check('GGDFG94'):
    print("You are allowed to look this username up.")
else:
    print("Your username contains special characters. Disallowed.")

Answer 4

def checkifallowed(string):
    whitelist = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
                 'u', 'v', 'w', 'x', 'y', 'z', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0']
    for i in string:
        if i not in whitelist:
            return False
    return True


somethingtocompare = input('What is the username that you want to look up?')
if checkifallowed(somethingtocompare):
    print('You can search this name up')
else:
    print('Disallowed.')

这只是定义一个函数，该函数检查白名单中的所有字符，并返回True或False。以下代码只是要求输入并返回结果。

Answer 5

使用正则表达式查找模式匹配

pattern= r"^[a-z,A-Z,0-9\s]+$"

myval="robotic@934"

#cons,args=re.search(pattern,input).groups()
all_matches=re.findall(pattern, myval)
print(all_matches)

输出： []

只允许某些字符

5 个答案: