Python学习笔记（六）之 面向对象

>>> class Foo:
    def __init__(self,name,age):   #构造方法，根据类创建对象时自动执行
        self.name = name
        self.age = age

>>> obj1 = Foo(‘小明‘,12) #将小明和12放到obj1/self的name和age中
>>> obj2 = Foo(‘小花‘,10)
#self 是一个形式参数，当执行 obj1 = Foo(‘小明‘,12) 时，self 等于 obj1
  当执行 obj2 = Foo(‘小花‘,10) 时，self 等于 obj2
>>> print (obj1)
<__main__.Foo object at 0x0000000003164A90> #内存地址
#通过对象直接调用被封装的内容，对象.属性名
>>> print (obj1.name)
小明
>>> print (obj1.age)
12
>>> print ( obj2.name,obj2.age)
小花 10

  #通过self间接调用被封装的内容

  #执行类中的方法时，需要通过self间接调用被封装的内容

class Foo:

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

　　　　def detail(self): 
　　　　　　print self.name 
　　　　　　print self.age 

obj1 = Foo(‘小明‘,12) 

obj1.detail() # Python默认会将obj1传给self参数，即：obj1.detail(obj1)，所以，此时方法内部的 self ＝ obj1，即：self.name 是 小明 ；self.age 是 12

#!/usr/bin/python3  
  
#类定义  
class people:  
    #定义基本属性  
    name = ‘‘  
    age = 0  
    #定义私有属性,私有属性在类外部无法直接进行访问  
    __weight = 0  
    #定义构造方法  
    def __init__(self,name,age,weight):  
        self.name = name  
        self.age = age
        self.__weight = weight  
    def speak(self):  
        print("%s 说: 我 %d 岁。" %(self.name,self.age))  
  
# 实例化类  
p = people(‘小明‘,10,30)  
p.speak()
print (p.weight)

#!/usr/bin/python3  
  
#类定义  
class people:  
    #定义基本属性  
    name = ‘‘  
    age = 0  
    #定义私有属性,私有属性在类外部无法直接进行访问  
    __weight = 0  
    #定义构造方法  
    def __init__(self,n,a,w):  
        self.name = n  
        self.age = a  
        self.__weight = w  
    def speak(self):  
        print("%s 说: 我 %d 岁。" %(self.name,self.age))  
  
#单继承示例  
class student(people):  
    grade = ‘‘  
    def __init__(self,n,a,w,grade):  
        #调用父类的构函  
        people.__init__(self,n,a,w)  
        self.grade = grade
    #覆写父类的方法  
    def speak(self):  
        print("%s 说: 我 %d 岁了，我在读 %d 年级"%(self.name,self.age,self.grade))
s = student(‘ken‘,10,60,3)  
s.speak()

# 类的继承-多继承
 
class People(object):       #新式类
    def __init__(self, name, age):
        self.name = name
        self.age = age
 
    def eat(self):
        print("%s is eating..." % self.name)
 
    def sleep(self):
        print("%s is sleeping...." % self.name)
 
class Relation(object):
    def make_friends(self,obj):
        print("%s is making friends with %s"%(self.name,obj.name))
 
class Man(Relation,People):             #多继承
    def play(self):
        print("%s is playing...." % self.name)
 
class Woman(People):
    def get_birth(self):
        print("%s is born a boby...." % self.name)
 
m1 = Man("lianzhilie", 22)
w1 = Woman("Alex", 33)
 
m1.make_friends(w1)
#lianzhilie is making friends with Alex

#经典类
 
class A():
    def __init__(self):
        print("A")
class B(A):
    pass
 
class C(A):
    def __init__(self):
        print("C")
 
class D(B,C):
    pass
 
obj = D()
#A
 
 
#新式类
 
class A(object):
    def __init__(self):
        print("A")
 
class B(A):
    pass
 
class C(A):
    def __init__(self):
        print("C")
 
class D(B,C):
    pass
 
obj = D()
#C

#多态
class Animal:
    def __init__(self, name):  # Constructor of the class
        self.name = name
 
    @staticmethod
    def animal_talk(obj):
        obj.talk()
 
class Cat(Animal):
    def talk(self):
        print(‘%s:Meow!‘%(self.name))
 
class Dog(Animal):
    def talk(self):
        print(‘%s:Woof! Woof!‘%(self.name))
 
c = Cat(‘Missy‘)
d = Dog(‘Lassie‘)
 
Animal.animal_talk(c)
Animal.animal_talk(d)
 
# Missy:Meow!
# Lassie:Woof! Woof!