找到指向某個對象的所有對象？ （python）

Question

如果我有一些對象的ID例如，我怎樣才能找出所有指向它的對象？

Answer 1

import gc 

class Node(object): 
    def __init__(self, data): 
     self.data = data 
     self.next = None 

if __name__ == "__main__": 
    a = Node(5) 
    a.next = Node(4) 
    a.next.next = Node(3) 
    # returns a list of dictionary of the object(s) referring to a.next.next 
    diction = gc.get_referrers(a.next.next)[0] 
    diction['next'] = None 
    print a.next.next 

垃圾收集器有一些巧妙的功能

get_referrers(...) 
    get_referrers(*objs) -> list 
    Return the list of objects that directly refer to any of objs. 

get_referents(...) 
    get_referents(*objs) -> list 
    Return the list of objects that are directly referred to by objs.