Python速成课程9-8，属性问题

Question

class User():

  def __init__(self,first,last,sex,age):
    self.first_name=first
    self.last_name=last
    self.sex = sex
    self.age =age
    self.login_attempts = 0

  def describe_users(self):
    print(self.first_name + " " +self.last_name)
    print("Gender: " + self.sex)
    print("Age: " + str(self.age))

  def greeting_users(self):
    print("Welcome, " + self.first_name + " " + self.last_name + "!\n")

  def increment_login_attempts(self):
    self.login_attempts += 1
    print("Login attempts: " + str(self.login_attempts))

  def reset_login_attempts(self):
    self.login_attempts = 0
    print("Login has been reset")

class Privileges():

  def __init__(self,privileges):
    self.privileges= ['can add post','can delete post', 'can ban user']

  def show_privileges(self):
    for x in self.privileges:
      print("The Admin can " + x)

class Admin(User):

  def __init__(self,first,last,sex,age):
    """Initialize attributes of the parent class"""
    super().__init__(first,last,sex,age)
    self.privileges = Privileges()

person_admin= Admin('Kevin','Mark','M',30)
person_admin.Privileges.show_privileges()

所以我在解决这个问题上遇到了困难。我一直收到error Typeerror。想知道你们中是否有人知道问题出在哪里？这个问题的目标是在"Admin“类中创建一个"Privileges”实例作为属性。之后，创建"Admin“的新实例，并使用"show_privileges”显示其权限。

Answer 1

确切的错误可能是这样的：

Traceback (most recent call last):
  File "python", line 42, in <module>
  File "python", line 40, in __init__
TypeError: __init__() missing 1 required positional argument: 'privileges'

这是因为您已经为Privileges编写了需要一个参数的构造函数，但在Admin的构造函数中实例化Privileges时没有传递该参数。只需将Privileges的构造函数更改为：

def __init__(self):  # removed argument "privileges"
    self.privileges = ['can add post','can delete post', 'can ban user']

然后，在最后一行，您将希望Privileges小写，因为您引用的是实例而不是类。

person_admin.privileges.show_privileges()

您可以查看working code here。