python - 如何让 __str__ 或 __repr__ 返回当前类的名称？

Question

我有这个代码:

class Employee:
    def __init__(self, name, pay, gender):
        self.name = name
        self.pay = pay
        self.gender = gender

    def add_raise(self):
        self.pay = int(self.pay*1.10)

    def __str__(self):
        if self.gender == "Female" or self.gender == "female":
            return f"{__class__.__name__} name: {self.name}, and she earns {self.pay} Pound"
        else:
            return f"{__class__.__name__} name: {self.name}, and he earns {self.pay} Pound"

    def __repr__(self):
        if self.gender == "Female" or self.gender == "female":
            return f"{__class__.__name__} name: {self.name}, and she earns {self.pay} Pound"
        else:
            return f"{__class__.__name__} name: {self.name}, and he earns {self.pay} Pound"

class Supervisor(Employee):
    def __init__(self, name, pay, gender, department):
        super().__init__(name, pay, gender)
        self.department = department

现在，当我尝试运行时

emp1 = Employee("Ron", 1000, "male")
emp10 = Supervisor("Hermoine", 3000, "female", "General")
print(emp1, emp10)

我只在开头得到“员工姓名”。如何更改它以反射(reflect)“Hermoine”是 Supervisor 而不仅仅是 Employee，而无需重写 __str__ 和__repr__ 方法？

Answer 1

解决方案:

尝试将您的第一个类改为:

class Employee:
    def __init__(self, name, pay, gender):
        self.name = name
        self.pay = pay
        self.gender = gender

    def add_raise(self):
        self.pay = int(self.pay*1.10)

    def __str__(self):
        if self.gender == "Female" or self.gender == "female":
            return f"{self.__class__.__name__} name: {self.name}, and she earns {self.pay} Pound"
        else:
            return f"{self.__class__.__name__} name: {self.name}, and he earns {self.pay} Pound"

    def __repr__(self):
        if self.gender == "Female" or self.gender == "female":
            return f"{self.__class__.__name__} name: {self.name}, and she earns {self.pay} Pound"
        else:
            return f"{self.__class__.__name__} name: {self.name}, and he earns {self.pay} Pound"

在所有字符串中尝试 self.__class__.__name__ 而不是 __class__.__name__。

现在:

emp1 = Employee("Ron", 1000, "male")
emp10 = Supervisor("Hermoine", 3000, "female", "General")
print(emp1, emp10)

输出:

Employee name: Ron, and he earns 1000 Pound Supervisor name: Hermoine, and she earns 3000 Pound

说明:

self之所以返回实际的类名，是因为它会从当前的self实例中提取类名。没有 self 只会得到原始父类的类名，而不是它当前所在的实际类，这就是 self 如此重要的原因。

正如@MadPhysicist 提到的，它是“因为 __class__ 在类执行时是词法范围的”。