functools.lru_cache

Question

functools.lru_cache

Accepted Answer

lru_cache memoizes function calls: the first call with a given set of arguments runs the function and stores the result; subsequent calls with the same arguments return the cached value immediately. The default maxsize=128 means at most 128 distinct argument combinations are cached; older entries are evicted first (Least Recently Used). Use @lru_cache(maxsize=None) for an unbounded cache - Python 3.9+ provides @functools.cache as a shorthand. Arguments must be hashable, so lists and dicts cannot be cache keys - a common gotcha when memoizing functions that accept sequences.