https://nalar.dev/tags/functools/ Recent content in Functools on Nalar Hugo en-us Wed, 02 Sep 2026 00:00:00 +0700 https://nalar.dev/cache-pure-work-with-functools-cache-and-lru-cache/ Wed, 02 Sep 2026 00:00:00 +0700 https://nalar.dev/cache-pure-work-with-functools-cache-and-lru-cache/ <p>Caching can turn repeated expensive work into a dictionary lookup, but it can also return stale data or grow memory without bound. Python&rsquo;s <code>functools</code> module provides two convenient memoization decorators: <code>lru_cache</code> and <code>cache</code>.</p> <p><code>functools.cache</code> has been available since Python 3.9. It is effectively an unbounded memoization cache. <code>lru_cache</code> adds a configurable size limit and eviction behavior.</p> <h2 id="cache-functions-not-arbitrary-side-effects">Cache functions, not arbitrary side effects</h2> <p>Memoization works best when a function behaves like a pure function: the result depends only on its arguments.</p>