Wrote a memoize function: I do not mind feedback

Albert-Jan Roskam fomcl at yahoo.com
Mon Apr 27 22:35:18 CEST 2015

----- Original Message -----
> From: Peter Otten <__peter__ at web.de>
> To: python-list at python.org
> Cc: 
> Sent: Monday, April 27, 2015 4:28 PM
> Subject: Re: Wrote a memoize function: I do not mind feedback
> Cecil Westerhof wrote:
>>  I started again with Python. In Clojure you have memoize. I thought it
>>  nice to have this in Python also. So I wrote it. With a Fibonacci
>>  function to show the usefulness.
>>  You can find it here:
>>     https://github.com/CecilWesterhof/PythonLibrary
>>  I love to hear what you think of it.
>>  And ideas for other functionalities are welcome also. Übung macht den
>>  Meister.
> See also: 
> https://docs.python.org/dev/library/functools.html#functools.lru_cache
> A bit hard to find unless you already know it's there.

If you Google for memoization decorator, you will easily find many more implementations. Not 100 percent sure, but I think the LRU cache decorator was not exactly light weight. I also like this one from Martelli's Python Cookbook, where he uses a mutable default argument {a dictionary} to implement memoization. I believe I went like this:

def some_func(arg, _memoize={}):
        return _memoize[arg]
    except KeyError:
        result = some_expensive_operation(arg)
        _memoize[arg] = result
        return result

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