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Re: HASH question [message #75456 is a reply to message #75367]

Mon, 07 March 2011 12:32

pgrigis
Messages: 436
Registered: September 2007

Senior Member

On Mar 5, 8:41 am, Gray <grayliketheco...@gmail.com> wrote:
> Hi all,
>
> I have a bunch of information which I'd like to store in an organized
> fashion:
> ~IDs of some stars
> ~Stellar types
> ~Magnitudes and fluxes in different images
>
> One way I could store the information would be as an array of
> structures, with each element being a single star, but I don't a
> priori know how many stars I have, and to find a particular star I'd
> have to search on the ID element. So, I could use a HASH of
> structures so I could index by ID, which would be ideal, but then
> assigning values to the individual tags of the structures is much more
> complicated. I could instead have a bunch of hashes, one for each type
> of information, but that would get pretty unwieldy.
>
> So, IDL gurus, anyone have a suggestion for how to organize this most
> efficiently and elegantly? Thanks!
>
> --Gray

Well since I don;t have IDL 8.0 yet. I can't really comment
on the hashes method, but what's wrong with an array of structures?

allstars=replicate({starID:'',spectralType:'',magnitude:0.0} ,
100)
allstars[0].starID='Sirius' & allstars[0].spectralType='A1' &
allstars[0].magnitude=-1.46
allstars[1].starID='Delta Pavonis' & allstars[1].spectralType='G8' &
allstars[1].magnitude=3.56
etc.

Single stars can easily be located with where:

ind=where(allstars.starID EQ 'Delta Pavonis',count)
if count EQ 1 then print,'The magnitude of '+allstars[ind].starID+' is
'+strtrim(allstars[ind].magnitude,2)

Ciao,
Paolo

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[Message index]

		HASH question By: Gray on Sat, 05 March 2011 05:41
		Re: HASH question By: penteado on Tue, 08 March 2011 10:15
		Re: HASH question By: pgrigis on Tue, 08 March 2011 10:12
		Re: HASH question By: penteado on Tue, 08 March 2011 07:56
		Re: HASH question By: David Fanning on Tue, 08 March 2011 07:11
		Re: HASH question By: pgrigis on Tue, 08 March 2011 07:05
		Re: HASH question By: Gray on Tue, 08 March 2011 04:23
		Re: HASH question By: chris_torrence@NOSPAM on Mon, 07 March 2011 13:38
		Re: HASH question By: penteado on Mon, 07 March 2011 13:05
		Re: HASH question By: penteado on Mon, 07 March 2011 13:02
		Re: HASH question By: chris_torrence@NOSPAM on Mon, 07 March 2011 13:00
		Re: HASH question By: pgrigis on Mon, 07 March 2011 12:32
		Re: HASH question By: Jeremy Bailin on Mon, 07 March 2011 11:15

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