From: Robert Klemme <shortcutter@...>
Date: 2006-08-14T06:05:09+09:00
Subject: Re: A use case for an ordered hash

Hal Fulton wrote:
> Robert Klemme wrote:
>> Hal Fulton wrote:
>>>
>>> I never use a hash for fast lookup. I use it because it
>>> allows me easily to associate an arbitrary key with a
>>> value.
>>
>> Um...  So you're saying that you wouldn't bother if lookups were 
>> O(n)?  Wow!
> 
> I think you mean "wouldn't care"?

Probably.  I'm not a native speaker so I'm certainly not authoritative 
on this matter. :-)

> Anyway: I'm happy that lookups are fast. But 99% of the time,
> my hashes are small enough that the time savings is probably
> very small in terms of program execution time.

That probably also depends on the frequency of lookups. :-)  But yes, my 
hashes are typically larger (although I also use small ones).

> If I were storing 20 million elements, I wouldn't use a Hash
> either. I'd either use a database or flat file; or if I
> needed it in RAM I might customize something (or likely use
> the red-black tree implementation).
 >
> I'm a late-optimizer. Until you mentioned it now, I had never
> thought of speed as a reason to use a hash. (Although, if you
> had asked me, I'd have said it was faster than O(n), of course.)

Interesting.

GoOd (n)ight

	robert

;-)