Re: What does del actually do?
John Nagle a écrit : The Python reference manual says, for del, Rather that spelling it out in full details, here are some hints. That's not too helpful. In particular, when del is applied to a class object, what happens? Are all the instance attributes deleted from the object? It would have been simpler to just test: class Ghost(object): ... def __init__(self, name): ... self.name = name ... say = whoo ... def greetings(self): ... print %s from %s %s \ ... %(self.say, self.__class__.__name__, self.name) ... g1 = Ghost(Albert) g2 = Ghost(Ivan) g1.greetings() whoo from Ghost Albert del Ghost g1.greetings() whoo from Ghost Albert g1.__class__ class '__main__.Ghost' the del statement remove a name from the current namespace. period. It's also used for removing keys from dicts. Is behavior the same for both old and new classes? Should it be different ? I'm trying to break cycles to fix some memory usage problems. GC and/or Weakrefs should do. -- http://mail.python.org/mailman/listinfo/python-list
What does del actually do?
The Python reference manual says, for del, Rather that spelling it out in full details, here are some hints. That's not too helpful. In particular, when del is applied to a class object, what happens? Are all the instance attributes deleted from the object? Is behavior the same for both old and new classes? I'm trying to break cycles to fix some memory usage problems. John Nagle -- http://mail.python.org/mailman/listinfo/python-list
Re: What does del actually do?
del simply removes the name in the current scope. if that happens to be the last non-cyclic reference to the object it was bound to, then it will remove the objec to, but thats a seperate matter. if you remove the class and there are instances out there, they can only exist if there are some other references to them, so no, they arent deleted. del wont just delete a bunch of objects and leave broken names. i has nothing to do with deleting objects, only names. On 2/10/07, John Nagle [EMAIL PROTECTED] wrote: The Python reference manual says, for del, Rather that spelling it out in full details, here are some hints. That's not too helpful. In particular, when del is applied to a class object, what happens? Are all the instance attributes deleted from the object? Is behavior the same for both old and new classes? I'm trying to break cycles to fix some memory usage problems. John Nagle -- http://mail.python.org/mailman/listinfo/python-list -- Read my blog! I depend on your acceptance of my opinion! I am interesting! http://ironfroggy-code.blogspot.com/ -- http://mail.python.org/mailman/listinfo/python-list
Re: What does del actually do?
Calvin Spealman wrote [top-posting, which I have corrected]: On 2/10/07, John Nagle [EMAIL PROTECTED] wrote: The Python reference manual says, for del, Rather that spelling it out in full details, here are some hints. That's not too helpful. In particular, when del is applied to a class object, what happens? Are all the instance attributes deleted from the object? Is behavior the same for both old and new classes? I'm trying to break cycles to fix some memory usage problems. del simply removes the name in the current scope. if that happens to be the last non-cyclic reference to the object it was bound to, then it will remove the object to, but thats a separate matter. if you remove the class and there are instances out there, they can only exist if there are some other references to them, so no, they arent deleted. del wont just delete a bunch of objects and leave broken names. i has nothing to do with deleting objects, only names. Except, of course, when you aren't deleting names but elements of some container object. The del statement removes references to objects as well as removing names from namespaces and elements from container objects. Calvin is correct, though. Since each instance of a class contains a reference to the class, the class will live on even after it is deleted by name, being garbage-collected only after all instances have ceased to exist. regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC/Ltd http://www.holdenweb.com Skype: holdenweb http://del.icio.us/steve.holden Blog of Note: http://holdenweb.blogspot.com See you at PyCon? http://us.pycon.org/TX2007 -- http://mail.python.org/mailman/listinfo/python-list
