__getattr__,__setattr__,__delattr__

class Dict(dict):
    def __getattr__(self,key): 
        return self[key]
    def __setattr__(self,key,value):
        dict.__setitem__(self,key,value)
    def __delattr__(self,key):
        dict.__delitem__(self,key)

if __name__==‘__main__‘:
    d=Dict(a=1,b=2)
    print d.a        #通过d.a获取d[‘a‘]
    d.a=2            #通过d.a修改d[‘a‘]
    print d[‘a‘]
    del d.a          #通过d.a删除d[‘a‘]
    try:
        print d[a]
    except NameError as e:
        print e