教授对 Python 作业的回答不会运行：TypeError: __init__() missing 1 required positional argument: 'gender'

Question

我确定以前有人问过这个问题，但我还没有达到能够理解其他问题如何回答我的水平。 有人可以解释这段代码的问题吗？ 我看不到：

class Person:
    name = ''
    age = 0
    gender = ''

    def __init__(self, name, age, gender):
        self.name = name
        self.age = age
        self.gender = gender


class Employee(Person):
    title = ''
    salary = 0

    def __init__(self, name, age, gender, title, salary):
        Person.__init__(name, age, gender)
        self.title = title
        self.salary = salary


George = Employee("George", 30, "Male", "Manager", 50000)
print("George's info is: Name is %s, Age is %d, Gender is %s, Title is %s, and Salary is %d" % (
George.name, George.age, George.gender, George.title, George.salary))

PyCharm 中返回的错误是：

Traceback (most recent call last):
  File "/Users/Sam/PycharmProjects/HW7/HW7-q2_Profs-Solution.py", line 22, in <module>
    George = Employee("George", 30, "Male", "Manager", 50000)
  File "/Users/DrewAndMon/PycharmProjects/HW7/HW7-q2_Profs-Solution.py", line 17, in __init__
    Person.__init__(name, age, gender)
TypeError: __init__() missing 1 required positional argument: 'gender'

Process finished with exit code 1

Answer 1

改变这一行：

        Person.__init__(name, age, gender)

到：

        Person.__init__(self, name, age, gender)

说明： Person.__init__方法有四个参数，第一个是被初始化对象的self参数。 通常， self参数的特殊之处在于它会自动获取调用该方法的对象的值。 但是，由于Person是一个类，而不是一个对象，在这种情况下，该方法不是在对象上调用的，因此必须将self参数作为显式参数传递。

更正常的做法是这样写：

        super().__init__(name, age, gender)

这看起来有点奇怪，但它避免了第二次不必要地写父类的名称，并且当一个类有两个超类时它可以正常工作。

Answer 2

需要改变的是对Employee类中的Person.__init__(name, age, gender)的调用，定义为def __init__(self, name, age, gender):
您的正确代码是-

class Person:
    name = ''
    age = 0
    gender = ''

    def __init__(self, name, age, gender):
        self.name = name
        self.age = age
        self.gender = gender


class Employee(Person):
    title = ''
    salary = 0

    def __init__(self, name, age, gender, title, salary):
        Person.__init__(self, name, age, gender)
        self.title = title
        self.salary = salary


George = Employee("George", 30, "Male", "Manager", 50000)
print("George's info is: Name is %s, Age is %d, Gender is %s, Title is %s, and Salary is %d" % (
George.name, George.age, George.gender, George.title, George.salary))

这会给你你的输出 -

George's info is: Name is George, Age is 30, Gender is Male, Title is Manager, and Salary is 50000