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class MyType(type): 
    def __init__(cls, what, bases=None, dict=None): 
        print 'call myType.__init__()'
        print "class name:"+what  
        print "class bases:"+str(bases) 
        print "class attributions:"+str(dict)
        super(MyType,cls).__init__(what, bases, dict)
    def __new__(cls, name, bases, attrs): 
        print "call MyType.__new__()"
        return type.__new__(cls, name, bases, attrs) 

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class num: 
    def __init__(self,v): 
        self.v=v 

    def double(self): 
        return self.v*2 


x=num(2) 
bound=x.double 

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data=pd.DataFrame([[2010,'auto'],[2010,'haha'],[2011,'haha'],[2012,'md']],columns=['year','type'])
data['typecnt']=np.ones(data.shape[0])
data.groupby(['year','type'])['typecnt'].count()

输出
year  type
2010  auto    1
      haha    1
2011  haha    1
2012  md      1

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