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