如何匹配 Python 字典中的键和值？

Question

我在名为“user_table.txt”的文本文件中有以下代表用户名和密码的数据：

Jane - valentine4Me
Billy 
Billy - slick987
Billy - monica1600Dress
 Jason - jason4evER
Brian - briguy987321CT
Laura - 100LauraSmith
   Charlotte - beutifulGIRL!
  Christoper - chrisjohn
Bruce - Bruce

然后我使用以下代码创建一个 Python 字典：

users = {}

with open("user_table.txt", 'r') as file:
    for line in file:
        line = line.strip()
    
        # if there is no password
        if ('-' in line) == False:
            continue
    
        # otherwise read into a dictionary
        else:
            key, value = line.split(' - ')
            users[key] = value
            
k= users.keys()
print(k)

以下代码是使用一些简单规则进行身份验证的函数：

a) 如果用户已登录（基于login_status），提示

b) 如果用户名在文件中不存在，则提示

c) 如果用户名存在，但与文件中的密码不匹配，则提示

这是（尝试）实现此功能的函数：

def authenticate(login_status, username, password):


    with open("user_table.txt", 'r') as file:
        for line in file:
            line = line.strip()
        
            # if there is no password
            if ('-' in line) == False:
                continue
        
            # otherwise read into a dictionary
            else:
                key, value = key, value = line.split(' - ')
                users[key] = value.strip()
                
    user_table= users.items()
    user_names = user_table.keys()
#    print(k)

    if login_status == True:
        print('User {} is already logged in.'.format(username))

    if username not in user_table.keys():
        print('username is not found')
    
    if username in user_table.keys() and password != user_table.get('value'):
        print('the password is incorrect')
        
    if username in user_table.keys() and password == user_table.get('value'):
        print('welcome to our new application')

当我调用以下内容时：

authenticate(False, 'Brian', 'briguy987321CT')

我收到这个错误：

AttributeError: 'dict_items' object has no attribute 'keys'

错误是由于：

if username not in user_table.keys():

知道错误在哪里吗？

提前致谢！

Answer 1

根据@khelwood 的建议，进行以下编辑解决了错误消息：

#    user_table= users.items()
#    user_names = user_table.keys()
    
#    print(k)

    if login_status == True:
        print('User {} is already logged in.'.format(username))

    if username not in users.keys():
        print('username is not found')
    
    if username in users.keys() and password != users.get('value'):
        print('the password is incorrect')
        
    if username in users.keys() and password == users.get('value'):
        print('welcome to our new application')

Answer 2

user_table 不是字典，而是一个类似集合的对象，它将字典中的每个条目保存为一个元组（即，{0:'a',1:'b',2:'c'}.items() 变为 dict_items([(0, 'a'), (1, 'b'), (2, 'c')])。该对象具有没有 .keys() 方法。

我认为你应该做的就是简单地使用字典 users:

    if login_status == True:
        print('User {} is already logged in.'.format(username))

    if username not in users.keys():
        print('username is not found')
    
    if (username in users.keys()) and (password != users.get('value')):
        print('the password is incorrect')
        
    if (username in users.keys()) and (password == users.get('value')):
        print('welcome to our new application')

（括号只是为了便于阅读）

如何匹配 Python 字典中的键和值？

How to match keys and values in a Python dictionary?

python

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