Python面向?qū)ο箢惱^承和組合實(shí)例分析

本文實(shí)例講述了Python面向?qū)ο箢惱^承和組合。分享給大家供大家參考，具體如下：

在python3中所有類默認(rèn)繼承object,凡是繼承了object的類都成為新式類，以及該子類的子類Python3中所有的類都是新式類，沒有集成object類的子類成為經(jīng)典類(在Python2中沒有集成object的類以及它的子類都是經(jīng)典類
繼承式用來創(chuàng)建新的類的一種方式，好處是減少重復(fù)代碼    
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()

執(zhí)行結(jié)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)

組合    
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()

執(zhí)行結(jié)果

    出生于<1995>年 <3>月 <16>日

繼承和組合    
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)

父類要限制

1、子類必須有父類的方法

2、子類實(shí)現(xiàn)的方法必須跟父類的方法的名字一樣    
import abc
class File(metaclass=abc.ABCMeta):
  @abc.abstractclassmethod
  def read(self):
    pass
  @abc.abstractclassmethod
  def write(self):
    pass