Circular references and python

François Pinard pinard at iro.umontreal.ca
Mon Jan 21 06:00:05 CET 2002


[Neel Krishnaswami]

> Manually freeing memory is ugly and error-prone.  Don't do it. :)

It might be the simplest approach in the long run, but there are still
many 1.5.2 implementations around, and you might want to write portably.

[Martin von Loewis]

> Consider

> class ListItem:
>   def __init__(self,next,prev):
>     self.prev,self.next = prev,next

> [...] To allow breaking the cycles, you can do

>   def clear(self):
>     if self.next:
>       self.next.clear()
>       self.next = None        # or self.prev = None

Here is my question.  Instead of:

    self.next = None

could one systematically write:

    del self.next

?  Is there any advantage, speed or otherwise, using one over the other?
The first might look more speedy, but since `del' is doomed to occur anyway
when the object is finalised, it is not so evident which is best.

-- 
François Pinard   http://www.iro.umontreal.ca/~pinard




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