python面向对象学习

Python是一种面向对象的编程语言，它支持面向对象编程（OOP）的所有基本概念，例如类、对象、继承、封装和多态性。下面是Python面向对象编程的一些基本概念和示例：

1.定义一个类

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

    def say_hello(self):
        print("Hello, my name is", self.name, "and I am", self.age, "years old.")

# 创建对象实例
person = Person("Alice", 25)
person.say_hello() # 输出：Hello, my name is Alice and I am 25 years old.

2.继承一个类

class Student(Person):
    def __init__(self, name, age, grade):
        super().__init__(name, age)
        self.grade = grade

    def say_hello(self):
        print("Hello, my name is", self.name, "and I am a student in grade", self.grade)

# 创建对象实例
student = Student("Bob", 18, 12)
student.say_hello() # 输出：Hello, my name is Bob and I am a student in grade 12.

3.封装一个类

class BankAccount:
    def __init__(self, balance):
        self.__balance = balance

    def deposit(self, amount):
        self.__balance += amount

    def withdraw(self, amount):
        if amount > self.__balance:
            print("Insufficient funds")
        else:
            self.__balance -= amount

    def get_balance(self):
        return self.__balance

# 创建对象实例
account = BankAccount(1000)
account.deposit(500)
account.withdraw(200)
print(account.get_balance()) # 输出：1300