@lru_cache on functions with no arguments
Serhiy Storchaka
storchaka at gmail.com
Thu Aug 3 11:55:19 EDT 2017
03.08.17 18:36, Ian Kelly пише:
> The single variable is only a dict lookup if it's a global. Locals and
> closures are faster.
>
> def simple_cache(function):
> sentinel = object()
> cached = sentinel
>
> @functools.wraps(function)
> def wrapper(*args, **kwargs):
> nonlocal cached
> if args or kwargs:
> return function(*args, **kwargs) # No caching with args
> if cached is sentinel:
> cached = function()
> return cached
> return wrapper
>
> *Zero* dict lookups at call-time. If that's not (marginally) faster
> than lru_cache with maxsize=None I'll eat my socks.
With salt?
$ ./python -m timeit -s 'from simple_cache import simple_cache; f =
simple_cache(int)' -- 'f()'
500000 loops, best of 5: 885 nsec per loop
$ ./python -m timeit -s 'from functools import lru_cache; f =
lru_cache(maxsize=None)(int)' -- 'f()'
1000000 loops, best of 5: 220 nsec per loop
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