如何创建具有多重继承的类

Question

我有这个代码：

class Person:
    def __init__(self, name, last_name, age):
        self.name = name
        self.last_name = last_name
        self.age = age 

class Student(Person):
    def __init__(self, name, last_name, age, indexNr, notes):
        super().__init__(name, last_name, age)
        self.indexNr = indexNr
        self.notes = notes

class Employee(Person):
    def __init__(self, name, last_name, age, salary, position):
        super().__init__(name, last_name, age)
        self.salary = salary
        self.position = position

class WorkingStudent(Student, Employee):
    def __init__(self, name, last_name, age, indexNr, notes, salary, position):
        Student.__init__(name, last_name, age, indexNr, notes)
        Employee.__init__(name, last_name, age, salary, position)

我想创建一个像这样的WorkingStudent实例：

ws = WorkingStudent("john", "brown", 18, 1, [1,2,3], 1000, 'Programmer')

但它不起作用，我收到此错误：

class Person:
    def __init__(self, name, last_name, age):
        self.name = name
        self.last_name = last_name
        self.age = age 

class Student(Person):
    def __init__(self, name, last_name, age, indexNr, notes):
        super().__init__(name, last_name, age)
        self.indexNr = indexNr
        self.notes = notes

class Employee(Person):
    def __init__(self, name, last_name, age, salary, position):
        super().__init__(name, last_name, age)
        self.salary = salary
        self.position = position

class WorkingStudent(Student, Employee):
    def __init__(self, name, last_name, age, indexNr, notes, salary, position):
        Student.__init__(name, last_name, age, indexNr, notes)
        Employee.__init__(name, last_name, age, salary, position)

或者我在这里做错了什么？另外，我已经super()在WorkingStudent类中尝试过，但它仅调用第一个传递的类的构造函数。即在这种情况下Student

注意：我已经进行了多次 StackOverflow 查询，但找不到任何可以回答这个问题的内容。（或者也许我错过了）。

Answer 1

super()使用mro 传递参数，而不是显式类：

class Person:
    def __init__(self, name, last_name, age):
        self.name = name
        self.last_name = last_name
        self.age = age 

class Student(Person):
    def __init__(self, name, last_name, age, indexNr, notes, salary, position):
        # since Employee comes after Student in the mro, pass its arguments using super
        super().__init__(name, last_name, age, salary, position)
        self.indexNr = indexNr
        self.notes = notes

class Employee(Person):
    def __init__(self, name, last_name, age, salary, position):
        super().__init__(name, last_name, age)
        self.salary = salary
        self.position = position

class WorkingStudent(Student, Employee):
    def __init__(self, name, last_name, age, indexNr, notes, salary, position):
        # pass all arguments along the mro
        super().__init__(name, last_name, age, indexNr, notes, salary, position)

# uses positional arguments            
ws = WorkingStudent("john", "brown", 18, 1, [1,2,3], 1000, 'Programmer')
# then you can print stuff like
print(f"My name is {ws.name} {ws.last_name}. I'm a {ws.position} and I'm {ws.age} years old.")
# My name is john brown. I'm a Programmer and I'm 18 years old.

检查先生：

WorkingStudent.__mro__
(__main__.WorkingStudent,
 __main__.Student,
 __main__.Employee,
 __main__.Person,
 object)

当您创建WorkingStudent 的实例时，最好传递关键字参数，这样您就不必担心弄乱参数的顺序。

由于WorkingStudent将属性的定义推迟到父类，因此立即使用层次结构向上传递所有参数，super().__init__(**kwargs)因为子类不需要知道它不处理的参数。第一个父类是 Student，因此 self.IndexNr 等定义在那里。mro 中的下一个父类是 Employee，因此从 Student 中，将剩余的关键字参数传递给它，super().__init__(**kwargs)再次使用。从 Employee 中，定义在那里定义的属性，并super().__init__(**kwargs)再次通过 mro（到 Person）传递其余的属性。

class Person:
    def __init__(self, name, last_name, age):
        self.name = name
        self.last_name = last_name
        self.age = age 

class Student(Person):
    def __init__(self, indexNr, notes, **kwargs):
        # since Employee comes after Student in the mro, pass its arguments using super
        super().__init__(**kwargs)
        self.indexNr = indexNr
        self.notes = notes

class Employee(Person):
    def __init__(self, salary, position, **kwargs):
        super().__init__(**kwargs)
        self.salary = salary
        self.position = position

class WorkingStudent(Student, Employee):
    def __init__(self, **kwargs):
        # pass all arguments along the mro
        super().__init__(**kwargs)

# keyword arguments (not positional arguments like the case above)
ws = WorkingStudent(name="john", last_name="brown", age=18, indexNr=1, notes=[1,2,3], salary=1000, position='Programmer')