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Re: Search routines [message #12844 is a reply to message #12829]

Fri, 18 September 1998 00:00

bowman
Messages: 121
Registered: September 1991

Senior Member

In article <MPG.106c1a47e9769edd9896bd@news.frii.com>, davidf@dfanning.com
(David Fanning) wrote:

> I thought that was the point of the WHERE function. :-)

I realize that WHERE will do the job, but at very low efficiency. WHERE
makes no assumptions about the list being ordered. It seems to me it has
to check every element of the array, requiring N steps for an N-element
array. This is even worse than a linear search of an ordered list, which
would require an average of N/2 steps. A simple bisection search would be
LOG2(N) on average, which is, of course, very advantageous for large N.

In article <36027091.59F@plato.sr.unh.edu>, Alexander Proussevitch
<alexp@plato.sr.unh.edu> wrote:

> Of course, there is such a routine. Check
>
> UNIQ !!!! It does any kind of search for you.

UNIQ seems to suffer from the same problem as WHERE, and I'm not sure what
use it is with floating point numbers.

Still looking ... ;-)

Ken

--
Dr. Kenneth P. Bowman, Professor 409-862-4060
Department of Meteorology 409-862-4466 fax
Texas A&M University bowmanATcsrp.tamu.edu
College Station, TX 77843-3150 Replace AT with @

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[Message index]

		Re: Search routines By: bowman on Fri, 18 September 1998 00:00
		Re: Search routines By: Liam Gumley on Fri, 18 September 1998 00:00
		Re: Search routines By: landsman on Fri, 18 September 1998 00:00
		Re: Search routines By: bowman on Fri, 18 September 1998 00:00
		Re: Search routines By: Alexander Proussevitc on Fri, 18 September 1998 00:00
		Re: Search routines By: davidf on Fri, 18 September 1998 00:00

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