> On 16 Jan 2022, at 18:44, Christopher Barker <python...@gmail.com> wrote:
>
> Is there no way to optimize the byte code without adding to the language?
>
> Not that it’s a bad idea anyway, but I wonder if frozen sets are common
> enough to warrant a change.
>
> Are there any performance advantages to a frozen set? I ask because I do
> often use sets that could be frozen, but don’t need to be. E.g. they don’t
> change, nor are they used as keys.
>
> For example:
>
> If flag in {‘the’, ‘allowable’, ‘flags’}:
> …
>
> If a frozen set was even a little bit faster or used less memory, it would be
> nice to be able to create one directly.
Not really relevant for the discussion, but CPython automaticly creates a
frozenset here (set display with immutable members) as an optimisation.
>>> dis.dis("x in {1,2,3}")
1 0 LOAD_NAME 0 (x)
2 LOAD_CONST 0 (frozenset({1, 2, 3}))
4 CONTAINS_OP 0
6 RETURN_VALUE
AFAIK the primary advantage of doing this is that the frozenset gets created
once instead of every time the expression is executed. Frozenset itself is not
faster than a regular set.
Ronald
—
Twitter / micro.blog: @ronaldoussoren
Blog: https://blog.ronaldoussoren.net/
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