python - 面向对象

面向内容与 java 一致，包含三大特点：封装、继承和多态。

定义一个对象

class Person:
    # 构造函数
    def __init__(self, name, age):
        self.name = name
        self.age = age

    # 定义一个函数
    def say_hello(self):
        print("Hello {}!".format(self.name))

    # 等价于 java 中的 toString()
    def __str__(self):
        return "Person(name: {}, age: {})".format(self.name, self.age)

    # python 表达式，用于重建对象
    def __repr__(self):
        # return f"Person('{self.name}', {self.age})"
        return "Person('{}', {})".format(self.name, self.age)


xiaoming = Person("xiaoming", 18)

print(xiaoming)
xiaoming.say_hello()

print(str(xiaoming))
print(repr(xiaoming))

print(eval(repr(xiaoming)))

print('hello world!!')

继承

class Student(Person):
    pass


a = Student('John', 23)
print(a)

print('hello world!!')