Memoization and encapsulation

[Steven D'Aprano]

On Fri, 30 Dec 2005 21:08:29 -0800, Raymond Hettinger wrote:

> Steven D'Aprano wrote:
>> I was playing around with simple memoization and came up with something
>> like this:

[snip]

> Try something like this:
> 
> def func(x, _cache={}):
>     if x in cache:
>         return cache[x]
>     result = x + 1 # or a time consuming function
>     return result

Of course. The most obvious thing is the least obvious :-)


> * If cache hits are the norm, then a try/except version would be a bit
> faster.
> 
> * In your original code, the global declaration wasn't needed because
> the assigment to _cache wasn't changed, rather its contents were.

Sure, it isn't needed, but I still like to make it explicit. Call it a
foible of mine :-)



-- 
Steven