Python中类的定义、继承及使用对象实例详解

>>> class pp:
...   pass
...
>>> p = pp()
>>> print p
<__main__.pp instance at 0x00CA77B0>
>>>

>>> class Person:
...   def __init__(self, name):
...       self.name = name
...   def sayHi(self):
...       print 'Hello, my name is', self.name
...
>>> p = Person('Swaroop')
>>> p.sayHi()
Hello, my name is Swaroop
>>>

>>> class Person:
...   population = 0
...   def __init__(self, name):
...       self.name = name
...       print '(Initializing %s)' % self.name
...   def __del__(self):
...       print '%s says bye.' % self.name
...       Person.population -= 1
...
...   def howMany(self):
...       if Person.population == 1:
...           print 'I am the only person here.'
...       else:
...           print 'We have %d persons here.' % Person.population
...
>>> A = Person('aa')
(Initializing aa)
>>> A.howMany()
We have 0 persons here.
>>> B = Person('bb')
(Initializing bb)
>>> B.howMany()
We have 0 persons here.
>>> ^Z
aa says bye.
bb says bye.

class CAnimal: 
       name = 'unname'
       # 成员变量 
  def __init__(self,voice='hello'):
  # 重载构造函数 
     self.voice = voice
     # 创建成员变量并赋初始值 
  def __del__(self):
  # 重载析构函数 
     pass # 空操作 
  def Say(self): 
      print self.voice 
t = CAnimal() # 定义动物对象t 
t.Say() # t说话 
>> hello # 输出 
dog = CAnimal('wow') # 定义动物对象dog 
dog.Say() # dog说话 
>> wow # 输出

class CAnimal: 
    def __init__(self,voice='hello'):
    # voice初始化默认为hello 
       self.voice = voice 
    def Say(self): 
      print self.voice 
 def Run(self): 
      pass # 空操作语句（不做任何操作） 
class CDog(CAnimal): # 继承类CAnimal 
  def SetVoice(self,voice): # 子类增加函数
     SetVoice self.voice = voice 
    def Run(self,voice): # 子类重载函数Run      
      print 'Running' 
bobo = CDog() 
bobo.SetVoice('My Name is BoBo!')
# 设置child.data为hello 
bobo.Say() 
bobo.Run() 
>> My Name is BoBo! 
>> Running