python檢查字典的用戶詳細信息

Question

usr_pwd = {'adam' : 'Test123', 'alice' : 'Test321'} 
u_name = input("Please specify your username: ") 
u_pwd = input("Please specify your password: ") 
usr_pwd[u_name] = u_pwd 
if usr_pwd.get(u_name) == u_pwd: 
    print('ok') 

我感到沮喪，需要一些幫助。如何檢查字典是否和給定用戶名和密碼組合是否有效？我找到了get模塊，但問題在於：

如果鍵在字典中，則返回鍵的值，否則爲默認值。如果未給出默認值，則默認爲None，以便此方法不會引發KeyError。

我還發現這Simple username and password application in Python但代碼：

if login in users and passw in users: # login matches password 
     print "Login successful!\n" 

不爲我工作...

Answer 1

有幾種流行的方式在dict檢查信息，每個人都有自己的地點。這裏有一些選項

usr_pwd = {'adam' : 'Test123', 'alice' : 'Test321'} 
u_name = input("Please specify your username: ") 
u_pwd = input("Please specify your password: ") 

# use get 
if usr_pwd.get(u_name) == u_pwd: 
    print('ok') 
else: 
    print('user name or password incorrect') 

# check first 
if u_name in usr_pwd: 
    if usr_pwd[u_name] == u_pwd: 
     print('ok') 
    else: 
     print('bad password') 
else: 
    print('bad user name') 

# try and die 
try: 
    if usr_pwd[u_name] == u_pwd: 
     print('ok') 
    else: 
     print('bad password') 
except: 
    print('bad user name')