On Mon, Jan 17, 2022 at 8:49 PM Steven D'Aprano <steve@pearwood.info> wrote:
On Mon, Jan 17, 2022 at 08:04:50PM +0900, Inada Naoki wrote:
Name lookup is faster than building set in most case. So I don't think cost to look name up is important at all.
But the cost to look up the name is *in addition* to building the set.
I meant it is negligible so we can just ignore it while this discussion.
If you saw this code in a review:
t = tuple([1, 2, 3, 4, 5])
would you say "that is okay, because the name lookup is smaller than the cost of building the list"?
I wouldn't. I would change the code to `(1, 2, 3, 4, 5)`.
* I never said it. I just said just lookup cost is not good reason because you listed name lookup cost for rationale. Please stop strawman. * tuple construction is much faster than set construction. So name lookup speed is more important for tuple. * Constant tuple is much much frequently used than constant set.
Proposed literal might have significant efficiency benefit only when:
* It is used in the function scope. and, * It can not be optimized by the compiler now.
Sometimes, now, the compiler *pessimizes* the construction of the frozen set. See b.p.o #46393.
I saw. And I know all the discussions in the b.p.o. already. But how important it is for Python depends on how often it is used, especially in hot code. Regards, -- Inada Naoki <songofacandy@gmail.com>