On Thu, Jun 25, 2009, Kristj?n Valur J?nsson wrote:
From: alex23
Kristj?n Valur J?nsson <krist...@ccpgames.com> wrote:
The idea is to speed up the swapping of list elemenst so that a.swap(b) is equivalent to a[:], b[:] = b[:], a[:] but without all the overhead of creating slices, assigning them and so forth.
I think I'd use a mapping to hold the lists so I could do a straight re-assignment:
d['a'], d['b'] = d['b'], d['a']
This is roughly equivalent to a, b = b, a right?
Yes and no. The point is that anyone holding a reference to ``d`` will see the changes to d['a'] and d['b'] (this would also apply to using an instance to proxy the changes through attributes). It's the usual trick for handling wholesale updates to mutable objects. Therefore it doesn't have the problem of the plain tuple-swap of losing the references. For any use-case that really is swapping as opposed to the fast initialization that you want, alex23's idea is a good kludge, which limits the scope of usefulness for what you want. -- Aahz (aahz@pythoncraft.com) <*> http://www.pythoncraft.com/ "as long as we like the same operating system, things are cool." --piranha