jfj at freemail.gr
Thu Jan 27 21:01:29 EST 2005
Nick Coghlan wrote:
> 1. Applies only if you are making large slices, or a lot of slices with
> each containing at least 3 elements.
> A view can also *cost* memory, when it looks at a small piece of a
> large item. The view will keep the entire item alive, even though it
> needs only a small piece.
That is correct.
> 2. Hell no. The *elements* aren't copied, pointers to the elements are.
> If you *don't* copy the pointers, then every item access through the
> view involves an indirection as the index into the original sequence
> gets calculated.
If you have
then you copy 100000 pointers AND you INCREF them AND you DECREF them
when y dies.
The unfortunate case by (1) would be:
> So views *may* save memory in some applications, but are unlikely to
> save time in any application (except any saving resulting from the
> memory saving).
They do. If tp_dealloc of a tuple view doesn't decref the pointers.
We should look for what is the most common case.
-PS: the PEP for the removal ought to have a ":)" at the end.
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