Python面向对象类继承和组合实例分析

本文实例讲述了Python面向对象类继承和组合。分享给大家供大家参考，具体如下：在python3

本文实例讲述了Python面向对象类继承和组合。分享给大家供大家参考，具体如下：

在python3中所有类默认继承object,凡是继承了object的类都成为新式类，以及该子类的子类Python3中所有的类都是新式类，没有集成object类的子类成为经典类(在Python2中没有集成object的类以及它的子类都是经典类

继承式用来创建新的类的一种方式，好处是减少重复代码

class People:
 def __init__(self,name,age):
 self.name=name
 self.age=age
 def walking(self):
 print('%s is walking ' %self.name)
 def talking(self):
 print('%s is talking '%self.name)
class Teacher(People):
 pass
class Student(People):
 pass
t1=Teacher('egon',18)
print(t1.name,t1.age)
t1.walking()
t1.talking()
s1=Student('xiaobai',22)
print(s1.name,s1.age)
s1.talking()
s1.walking()

执行结果

egon 18 egon is walking egon is talking xiaobai 22 xiaobai is talking xiaobai is walking

class People:
 def __init__(self,name,age,sex):
 self.name=name
 self.age=age
 self.sex=sex
 def walking(self):
 print('%s is walking ' %self.name)
 def talking(self):
 print('%s is talking '%self.name)
class Teacher(People):
 def __init__(self,name,age,sex,level,salary):
 People.__init__(name,age,sex)
 self.level=level
 self.salary=salary
 def teaching(self):
 People.talking(self)
 print('%s is teaching'%self.name)
class Student(People):
 def __init__(self,name,age,sex,group):
 People.__init__(name,age,sex)
 self.group=group
 def studying(self):
 People.talking(self)
 print('%s is studying'%self.name)

组合

class Date:
 def __init__(self,year,mon,day):
 self.year=year
 self.mon=mon
 self.day=day
 def tell_birth(self):
 print('出生于<%s>年 <%s>月 <%s>日'%(self.year,self.mon,self.day))
class Teacher:
 def __init__(self,name,age,sex,year,month,day):
 self.name=name
 self.age=age
 self.sex=sex
 self.birth=Date(year,month,day)
 def teaching(self):
 print('%s is teaching'%self.name)
class Student:
 def __init__(self,name,age,sex,year,mon,day):
 self.name=name
 self.age=age
 self.sex=sex
 self.birth=Date(year,mon,day)
 def studying(self):
 print('%s is studying'%self.name)
xiaobai=Student('xiaobai',22,'male','1995','3','16')
xiaobai.birth.tell_birth()

执行结果

出生于<1995>年 <3>月 <16>日

继承和组合

class People:
 def __init__(self,name,age,sex,year,mon,day):
 self.name=name
 self.age=age
 self.sex=sex
 self.birth=Date(year,mon,day)
 def walking(self):
 print('%s is walking ' %self.name)
 def talking(self):
 print('%s is talking '%self.name)
class Date:
 def __init__(self,year,mon,day):
 self.year=year
 self.mon=mon
 self.day=day
 def tell_birth(self):
 print('出生于<%s>年 <%s>月 <%s>日'%(self.year,self.mon,self.day))
class Teacher(People):
 def __init__(self,name,age,sex,level,salary,year,mon,day):
 People.__init__(self,name,age,sex,year,mon,day)
 self.level=level
 self.salary=salary
 def teaching(self):
 People.talking(self)
 print('%s is teaching'%self.name)
class Student(People):
 def __init__(self,name,age,sex,year,mon,day,group):
 People.__init__(self,name,age,sex,year,mon,day)
 self.group=group
 def studying(self):
 People.talking(self)
 print('%s is studying'%self.name)

父类要限制

1、子类必须有父类的方法

2、子类实现的方法必须跟父类的方法的名字一样

import abc
class File(metaclass=abc.ABCMeta):
 @abc.abstractclassmethod
 def read(self):
 pass
 @abc.abstractclassmethod
 def write(self):
 pass