Python中的Dunder方法实现小结

class Student:

    def __init__(self, name, score):

        self.name = name

        self.score = score

s = Student("张三", 95)

print(s.name)  # 输出: 张三

class FileHandler:

    def __del__(self):

        print("文件句柄已释放")

class Car:

    def __init__(self, brand):

        self.brand = brand

  
    def __str__(self):

        return f"汽车品牌: {self.brand}"

  
car = Car("特斯拉")

print(car)  # 输出: 汽车品牌: 特斯拉

def __repr__(self):

    return f'Car("{self.brand}")'

class Vector:

    def __init__(self, x, y):

        self.x = x

        self.y = y

  
    def __add__(self, other):

        return Vector(self.x + other.x, self.y + other.y)

  
v1 = Vector(1, 2)

v2 = Vector(3, 4)

v3 = v1 + v2

print(v3.x, v3.y)  # 输出: 4 6

def __eq__(self, other):

    return self.x == other.x and self.y == other.y

class MyList:

    def __init__(self, data):

        self.data = data

    def __len__(self):

        return len(self.data)


ml = MyList([1, 2, 3])

print(len(ml))  # 输出: 3

def __getitem__(self, index):

    return self.data[index]

class Multiplier:

    def __init__(self, factor):

        self.factor = factor

  


    def __call__(self, x):

        return x * self.factor
 


double = Multiplier(2)

print(double(5))  # 输出: 10

class Fraction:

    def __init__(self, numerator, denominator):

        self.numerator = numerator

        self.denominator = denominator

  


    def __str__(self):

        return f"{self.numerator}/{self.denominator}"

  


    def __add__(self, other):

        new_num = self.numerator * other.denominator + other.numerator * self.denominator

        new_den = self.denominator * other.denominator

        return Fraction(new_num, new_den)


f1 = Fraction(1, 2)

f2 = Fraction(1, 3)

result = f1 + f2

print(result)  # 输出: 5/6