Python OOP Basic

第一个简单的类

class FirstClass:                   #Define a class object
    def setdata(self, value):       #Define class methods
        self.data = value           #self is the instance

    def display(self):
        print(self.data)            #self.data: per instance

测试结果： 

 

继承

class FirstClass:                   #Define a class object
    def setdata(self, value):       #Define class methods
        self.data = value           #self is the instance

    def display(self):
        print(self.data)            #self.data: per instance



class SecondClass(FirstClass):      #Inherits setdata
    def display(self):              #Changes display
        print('Current value = "%s"' % self.data)

测试结果：

 

运算符重载

class FirstClass:                   #Define a class object
    def setdata(self, value):       #Define class methods
        self.data = value           #self is the instance

    def display(self):
        print(self.data)            #self.data: per instance



class SecondClass(FirstClass):      #Inherits setdata
    def display(self):              #Changes display
        print('Current value = "%s"' % self.data)



class ThirdClass(SecondClass):
    def __init__(self, value):                  #__init__方法，也称为构造函数方法，用于初始化对象的状态
        self.data = value

    def __add__(self, other):                   #运算符重载，"+"表达式会触发"__add__"方法
        return ThirdClass(self.data + other)

    #对于print，Python把要打印的对象传递给__str__中的self，该方法返回的字符串看做是对象的打印字符串
    def __str__(self):                          
        return '[ThirdClass: %s]' % self.data

    def mul(self, other):                       #in-place change: named
        self.data *= other

 测试结果：

 

一个简单完整的类

 

一个完整的例子(Encapsulation, Inheritance, Polymorphism)

class Person:
    def __init__(self, name, job=None, pay=0):
        self.name = name
        self.job = job
        self.pay = pay

    def getLastName(self):
        return self.name.split()[-1]

    def giveRaise(self, percent):
        self.pay = int(self.pay * (1 + percent))

    def __str__(self):
        return '[Person: %s, %s]' % (self.name, self.pay)

class Manager(Person):
    def __init__(self, name, pay):                      #Redefine constructor
        Person.__init__(self, name, 'manager', pay)
    
    def giveRaise(self, percent, bonus=.10):            #Redefine at this level
        Person.giveRaise(self, percent + bonus)         #Call Person's version

    def __str__(self):
        return '[Manager: %s, %s]' % (self.name, self.pay)

if __name__ == '__main__':
    p1 = Person('Michael Jordan')
    p2 = Person('Kobe Bryant', job='developer', pay=100000)
    print(p1)
    print(p2)
    print(p1.getLastName(), p2.getLastName())
    p2.giveRaise(.10)                         
    print(p2)

    p3 = Manager("David Stern", 50000)
    p3.giveRaise(.10)
    print(p3.getLastName())
    print(p3)

    print('--All three--')
    for object in (p1, p2, p3):
        object.giveRaise(.10)
        print(object)

测试结果：