Python基础之面向对象

1.构造函数

 

class test:
    def __init__(self,name1,age1):
        self.name = name1              ## __init__即为构造函数,初始化实例赋予指定的属性,self代表实例    
                                       ##对象本身,类中定义属性和方法时需默认加上self
        self.age = age1

a = test('aimar','18')
print ('%s is %s' %(a.__name,a.__age))
        

 

　　

2. 私有属性和方法

class test:
    def __init__(self,name1,age1):
        self.__name = name1              ## 变量名前加入两个下划线__ 即代表私有，外部无法访问
        self.__age = age1

a = test('aimar','18')
print ('%s is %s' %(a.__name,a.__age))


Traceback (most recent call last):
  File "C:/Users/Administrator/PycharmProjects/untitled/test.py", line 92, in <module>
    print ('%s is %s' %(a.__name,a.__age))
AttributeError: 'test' object has no attribute '__name'

　　

3.类的三大特性之一:封装

 

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

    def kanchai(self):
        print('%s is %s years old ,上山去砍柴' %(self.name,self.age))

    def kaiche(self):
        print ('%s is %s years old,开车去东北' %(self.name,self.age))

    def baojian(self):
        print ('%s is %s years old,大保健！' %(self.name,self.age))

p1 = test('小明','18')
p2 = test('老李','90')

p1.kanchai()
p1.kaiche()
p1.baojian()

p2.kanchai()
p2.kaiche()
p2.baojian()

#########################################
小明 is 18 years old ,上山去砍柴
小明 is 18 years old,开车去东北
小明 is 18 years old,大保健！
老李 is 90 years old ,上山去砍柴
老李 is 90 years old,开车去东北
老李 is 90 years old,大保健！

 

4.类的三大特性之一:继承

class People:
    def chifan(self):
        print('%s eat food' %self.name)

    def shuijiao(self):
        print('%s sleep' %self.name)

class Man(People):

    def __init__(self,name):
        self.name = name

    def sport(self):
        print ('%s play soccer' %self.name)

class Women(People):

    def __init__(self,name):
        self.name = name
        
    def entertainment(self):
        print ('%s shopping' %self.name)

M1 = Man('小明')
M2 = Women('小王')

M1.chifan()
M1.sport()
M2.chifan()
M2.entertainment()


###############################
小明 eat food
小明 play soccer
小王 eat food
小王 shopping