Python 类与对象

类与对象是面向对象编程的两个主要方面。

#创建一个名叫 Person 的类
class Person:
    
    def __init__(self,name):
        self.name = name
        
    def say_hi(self):#def 方法
        print("my name is {}".format(self.name))

p = Person("jimmy") #给Person类创建一个对象p或实例p
p.say_hi()

(output：)my name is jimmy 

• 1，2参数传递给方法.
• 3 self参数指向当前实例自身.
• 4 我们不需要传递实例自身给方法，Python解释器自己会做这些操作的.

__init__方法

__init__方法会在类的对象被实例化时（p = Person("jimmy")）立即运行。这方法可以对任何你想进行操作的目标对象进行初始化操作。

self

类方法与普通函数的区别在于多了一个self名称。当你调用功能时，Pyhton会自动为该参数赋值。

没有参数的实例方法也必须拥有一个参数——self.

继承

下面这段代码引用自《a byte of python》

class SchoolMember:
    """公用类，父类型"""
    def __init__(self, name, age):
        self.name = name
        self.age = age
        print(('Initialized SchoolMember:{}').format(self.name))


    def tell(self):
        """tell me more"""
        print('name:"{}" Age:"{}"'.format(self.name, self.age),end = " ")


class Teacher(SchoolMember):#子类型
    """代表一个老师"""
    def __init__(self, name, age, salary):
        SchoolMember.__init__(self, name, age)
        self.salary = salary
        print('Initialized Teacher:{}'.format(self.name))

    def tell(self):
        SchoolMember.tell(self)
        print('Salary:"{:d}"'.format(self.salary))


class Student(SchoolMember):#子类型
    """代表一个学生"""
    def __init__(self, name, age, marks):
        SchoolMember.__init__(self, name, age)
        self.marks = marks
        print('Initialized Student:{}'.format(self.name))

    def tell(self):
        SchoolMember.tell(self)
        print('marks:"{:d}"'.format(self.marks))


if __name__ == '__main__':
    t = Teacher('Mrs. Shrividya',40 ,30000)
    s = Student('XiaoMing', 20, 75 )
    print()
    members = [t,s]
    for member in members:
        member.tell()

output:        
Initialized SchoolMember:Mrs. Shrividya
Initialized Teacher:Mrs. Shrividya
Initialized SchoolMember:XiaoMing
Initialized Student:XiaoMing