| Re: Where vs Histogram vs ?? [message #32522] |
Thu, 17 October 2002 06:58  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Andrew Cool (andrew.cool@dsto.defence.gov.au) writes:
> I have a structure defined as :-
>
> data_st = {YEAR : 0 ,$
> DAY : 0 ,$ ; 136 days over 12 years
> HALF_HR : 0 ,$ ; 0..47
> RANGE_IDX : 0 ,$ ; 0..267
> WRF : 0B ,$ ; 3 possible values
> FREQ : 0B ,$ ; 4 possible values
> BEAM : 0B ,$ ; 4 possible values
> PAD : 0B ,$ ; Padding to align byte
> boundaries
> Parameter : FLTARR(5)}
>
>
> Replicate that a few times :-
>
> database = Replicate(data_st,15425228)
15425228!? The mind boggles. :-(
In a *structure*!? I guess it would be slow. I think I would
lean toward some kind of flat file structure that could be accessed
quickly with associated variables and an array (arrays?) of
pointers.
> Is there a quicker way than the above monsterous Where statement?
> I've browsed the Histogram tut on David Fanning's site, and rapidly found
> my eyes glazing over. Can Histogram help here? Perhaps multiple nested
> Histograms? David's SetUnion or SetIntersection, maybe?
SetUnion and SetIntersection are just fancy wrappers to Histogram.
Cheers,
David
P.S. Let's just say I'm pretty sure my lack of good ideas
this morning has to do with the excessive celebration after
beating that 25 year-old kid again last night. (On a service
ace and an overhead, if you can imagine!) Oooohh, that kid
hates to play me. But I think that is the last time he will
call me "Grandpa." :-)
--
David W. Fanning, Ph.D.
Fanning Software Consulting, Inc.
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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