为什么我收到错误：AttributeError：'builtin_function_or_method'对象没有属性'isdigit'

Question

我正在创建一个登录系统，在注册时要求用户输入用户名和密码。我使用了一个函数来检查用户名是否有效，然后根据要求查看密码是否有效。（用户名不能已经在使用，必须包含字母）（密码必须包含大写、小写和数）。用户名函数完美运行，但由于某种原因在密码函数中我收到错误： AttributeError: 'builtin_function_or_method' object has no attribute 'isdigit' 有谁知道我在使一个函数和另一个函数之间的两个函数之间做的不同不是。谢谢。

    def Username(user_name):
    user_names = open('Username list.txt', 'r+')
    uname_list = user_names.readlines()
    char_user = [user_name]
    for i in range(len(uname_list)):
        uname_list[i] = uname_list[i].strip('\n')
    for i in range(len(uname_list)):
        if uname_list[i] == user_name:
            return 'username already taken'
    for i in range(len(char_user)):
        if char_user[i].isspace() == True:
            return 'username cannot contain spaces' 
    if user_name.isdigit() == True:
        return 'username must contain letters'
    elif len(user_name) < 4 or len(user_name) > 12:
        return 'username must be between 4 and 12 characters'
    else:
        user_names.write(str(user_name + '\n'))
        file.close(user_names)
        return True

def Password(password, p2):
    passwords = open('Password list.txt', 'r+')
    if password != p2:
        return 'you did not enter the same password twice'
    elif password.isdigit() == True:
        return 'username must contain letters'
    elif password.islower() == True:
        return 'username must contain a capital letter'
    elif password.isupper() == True:
        return 'username must contain a lower case letter' 
    elif password.isalpha() == True:
        return 'username must contain a number'
    elif len(user_name) < 4 or len(user_name) > 12:
        return 'username must be between 4 and 12 characters'
    else:
        passwords.write(str(password + '\n'))
        return True 


print 'What would you like your username to be?'        
print  'Your username must be between 4 and 12 characters, contain letters and not contain any spaces'
user_name = raw_input()
valid = Username(user_name)
while valid != True:
    print valid
    user_name = raw_input()
    valid = Username(user_name)

print 'enter your password twice below for validication'
password = raw_input()
password2 = raw_input()
valid = Password(password,password2)
while valid != True:
    print valid
    print 'enter your password twice below'
    password = raw_input
    password2 = raw_input
    valid = Password(password,password2)

程序运行时会发生什么。

    '''What would you like your username to be?
    Your username must be between 4 and 12 characters, contain letters and not contain any spaces
    Test
    enter your password twice below for validication
    Your password must include capital letters, lowercase letters, numbers and be betweeen 4 and 12 characters
    testing
    testing
    username must contain a capital letter
    enter your password twice below
    AttributeError: 'builtin_function_or_method' object has no attribute 'isdigit'''

Answer 1

你只崇敬raw_input，但不要在最后两行调用它。

您的密码检查有问题。所有小写​​+数字或所有大写+数字都是有效密码。

Answer 2

当你调用一个函数时，你需要在它周围加上括号()：

>>> password = raw_input
>>> password.isdigit() 
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'builtin_function_or_method' object has no attribute 'isdigit'
>>> password = raw_input()
67
>>> password.isdigit()
True
>>> 

这是您的更新代码：

def Username(user_name):
    user_names = open('Username list.txt', 'r+')
    uname_list = user_names.readlines()
    char_user = [user_name]
    for i in range(len(uname_list)):
        uname_list[i] = uname_list[i].strip('\n')
    for i in range(len(uname_list)):
        if uname_list[i] == user_name:
            return 'username already taken'
    for i in range(len(char_user)):
        if char_user[i].isspace() == True:
            return 'username cannot contain spaces' 
    if user_name.isdigit() == True:
        return 'username must contain letters'
    elif len(user_name) < 4 or len(user_name) > 12:
        return 'username must be between 4 and 12 characters'
    else:
        user_names.write(str(user_name + '\n'))
        file.close(user_names)
        return True

def Password(password, p2):
    passwords = open('Password list.txt', 'r+')
    if password != p2:
        return 'you did not enter the same password twice'
    elif password.isdigit() == True:
        return 'username must contain letters'
    elif password.islower() == True:
        return 'username must contain a capital letter'
    elif password.isupper() == True:
        return 'username must contain a lower case letter' 
    elif password.isalpha() == True:
        return 'username must contain a number'
    elif len(user_name) < 4 or len(user_name) > 12:
        return 'username must be between 4 and 12 characters'
    else:
        passwords.write(str(password + '\n'))
        return True 


print 'What would you like your username to be?'        
print  'Your username must be between 4 and 12 characters, contain letters and not contain any spaces'
user_name = raw_input()
valid = Username(user_name)
while valid != True:
    print valid
    user_name = raw_input()
    valid = Username(user_name)

print 'enter your password twice below for validication'
password = raw_input()
password2 = raw_input()
valid = Password(password,password2)
while valid != True:
    print valid
    print 'enter your password twice below'
    password = raw_input()
    password2 = raw_input()
    valid = Password(password,password2)

在你的文件中间你正确地调用了raw_input()，但你最后忘记了。简单的 python 错误，几乎和使用 == 而不是 = 或其他方式一样常见 :)