一、__len__()和__getitem__()

如果在类中定义了__getitem__()方法，那么他的实例对象（假设为P）就可以这样P[key]取值。当实例对象做P[key]运算时，就会调用类中的__getitem__()方法

# -*- coding:utf-8 -*-

class DataTest:

def __init__(self,id,address):

self.id=id

self.address=address

self.d={self.id:1,

self.address:"192.168.1.1"

}

def __getitem__(self,key):

return "hello"

data=DataTest(1,"192.168.2.11")

print data[2]

 

二、字典定制

class Countlist:

def __init__(self, *args):

self.values = [x for x in args]

self.count ={}.fromkeys(range(len(self.values)),0)

def __len__(self):

return len(self, values)

def __getitem__(self, key):

self.count[key]+=1

return self.values[key]