I was playing around with simple memoization and came up with something
like this:
_cache = {}
def func(x):
global _cache
if _cache.has_key(x):
return _cache[x]
else:
result = x+1 # or a time consuming calculation...
_cache[x] = result
return result
when it hit me if I could somehow bind the cache to the function, I could
get rid of that pesky global variable.
I tried this:
>>> def func(x):
... try:
... func.cache
... except AttributeError:
... func.cache = {}
... if func.cache.has_key(x):
... return func.cache[x]
... else:
... result = x + 1
... func.cache[x] = result
... return result
and it works as expected, but it lacks elegance.
Instead of using a function, I can also use a new-style class as if it
were a function:
>>> class Func(object):
... cache = {}
... def __new__(self, x):
... if self.cache.has_key(x):
... return self.cache[x]
... else:
... result = x+1
... self.cache[x] = result
... return result
and again it works, but I can't help feeling it is an abuse of the class
mechanism to do this.
What do folks think? Is there a better way?
--
Steven.
--
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