| Re: Indexing structures of different type [message #15914] |
Thu, 17 June 1999 00:00 |
Craig Markwardt
Messages: 1869
Registered: November 1996
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Senior Member |
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Donglai Gong Rm3110 x1569 <donglai@eden.rutgers.edu> writes:
>
> Hi, does anyone know how to index structures of different types in IDL?
>
> REPLICATE won't work since it creates an array of the same structure, so
> I'm thinking of doing a structure of structures. However I don't know
> how to index them for use in a loop. Thanks in advance.
If you are *really* trying to glue a bunch of different types
together, you should probably structures as you say.
How to loop over them? This is easily done with a little magic:
;; Initialize your structure
s = {u:0L, v:0D, w:intarr(5), x:{a:1, b:2}, y:'hello'}
n = n_tags(s)
for i = 0L, n-1 do begin
;; The magic is here:
f = s.(i)
;; Operate on f here:
print, f
endfor
However, you should be aware that IDL structures are pretty slow to
operate on, especially when you build large ones. [ Some versions of
IDL have a limit on the number of elements in a structure too. ]
Good luck,
Craig
--
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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@astrog.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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| Re: Indexing structures of different type [message #15916 is a reply to message #15914] |
Thu, 17 June 1999 00:00  |
Liam Gumley
Messages: 473
Registered: November 1994
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Senior Member |
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Donglai Gong Rm3110 x1569 wrote:
> Hi, does anyone know how to index structures of different types in IDL?
> REPLICATE won't work since it creates an array of the same structure, so
> I'm thinking of doing a structure of structures. However I don't know
> how to index them for use in a loop. Thanks in advance.
Perhaps the following example might help:
a = {name:'test', value:intarr(10)}
b = {time:0L, lat:0.0, lon:0.0}
c = {part1:replicate(a, 100), part2:replicate(b, 20)}
help, a, b, c, /structure
print, c.part1[10].name
print, c.part1[10].value[0:5]
print, c.part2[15:*].time
Cheers,
Liam.
--
Liam E. Gumley
Space Science and Engineering Center, UW-Madison
http://cimss.ssec.wisc.edu/~gumley
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