On Mon, Jan 17, 2022 at 11:18:13PM +0900, Inada Naoki wrote:
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.
On my computer, the name lookup is almost a quarter of the time to build a set:
[steve ~]$ python3.10 -m timeit "frozenset" 10000000 loops, best of 5: 24.4 nsec per loop [steve ~]$ python3.10 -m timeit "{1, 2, 3, 4, 5}" 2000000 loops, best of 5: 110 nsec per loop
and about 10% of the total time:
[steve ~]$ python3.10 -m timeit "frozenset({1, 2, 3, 4, 5})" 1000000 loops, best of 5: 237 nsec per loop
If I use a tuple instead of the set, it is about 12% of the total time:
[steve ~]$ python3.10 -m timeit "frozenset((1, 2, 3, 4, 5))" 2000000 loops, best of 5: 193 nsec per loop
So not negligible.
That is in the global scope, which will be much slower than a local scope. Global builtins do a hash table lookup; local lookups just follow a
El lun, 17 ene 2022 a las 7:11, Steven D'Aprano (<steve@pearwood.info>) escribió: pointer.
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