我正在尝试学习 python OOP,但遇到以下错误。
Exception has occurred: NameError
name 'self' is not defined
File "/home/khalid/Desktop/MiniProject3/test1.py", line 27, in <module>
login = first_class (self.Bank_Users.keys(), self.Bank_Users.values())
File "/home/khalid/anaconda3/lib/python3.7/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/home/khalid/anaconda3/lib/python3.7/runpy.py", line 96, in _run_module_code
mod_name, mod_spec, pkg_name, script_name)
File "/home/khalid/anaconda3/lib/python3.7/runpy.py", line 263, in run_path
pkg_name=pkg_name, script_name=fname)
我试图寻找可能已解决的类似问题,但我找不到解决此错误的方法。
class first_class(object):
def __init__(self, UserName, Password, Bank_Users):
self.UserName = UserName
self.Password = Password
self.Bank_Users = {"Aldo": "1234"}
def login_or_exit(self):
while True:
print("Please Enter User Name")
self.UserName = input(">> ")
print("Please Enter Password")
self.Password = input(">> ")
if self.UserName in self.Bank_Users.keys() and self.Password in self.Bank_Users.values():
print("Logging into", self.UserName)
else:
print("Unsuccesful!!")
login = first_class (self.Bank_Users.keys(), self.Bank_Users.values())
login.login_or_exit()
正确执行此操作可能如下所示:
class BankLoginSystem(object):
def __init__(self, bank_users):
self.bank_users = bank_users
self.logged_in_user = None
def login_or_exit(self):
while True:
print("Please Enter User Name")
attempted_user = input(">> ")
print("Please Enter Password")
attempted_password = input(">> ")
if attempted_password == self.bank_users.get(attempted_user):
self.logged_in_user = attempted_user
print("Success!!")
return
else:
print("Unsuccesful!!")
# the user database is independent of the implementation
bank_users = { "Aldo": "1234" }
login = BankLoginSystem(bank_users)
login.login_or_exit()
print("Logged in user is: %s" % login.logged_in_user)
请注意,我们没有将用户名和密码作为对象的初始化参数——因为一个对象在其生命周期内可以有多个用户登录,所以这样做没有意义。
同样,应该保密的东西(比如尝试的密码)我们不会存储在类成员变量中,而是严格保持本地变量,这样它们就不会泄漏到范围之外。(在真实系统中,您希望您的密码数据库具有加盐哈希,而不是真正的密码,如果密码数据库本身泄漏,则包含损坏)。
顺便说一句,请注意,一般来说,将您的 I/O 逻辑与您的后端存储表示相结合是一个坏主意——通常,您希望将您的域建模的纯对象与与用户发生的任何交互分开并区别开来。
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我来说两句