| Re: Structure field concatenation [message #21666 is a reply to message #21614] |
Wed, 06 September 2000 07:16   |
Martin Schultz
Messages: 515
Registered: August 1997
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Senior Member |
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Amara Graps wrote:
>
> (at the risk of being the only one here who still hasn't
> figured this out)
>
Reset.
Now try again from scratch:
;; create template structure and structure array
template = {orbit:'',freq:ptr_new()}
periodcube = replicate(template, 20)
;; fill first element with data
periodcube.orbit = 'G2'
periodcube.freq = Ptr_New( DIndgen(100) )
;; Work with data
plot, *(periodcube.freq), title=periodcube.orbit
;; Free all pointers
Ptr_Free, periodcube.freq
You probably didn't want to use a second Ptr_New statement out of
fear that would allocate extra memory and create a memory leak.
This is no problem, because the Ptr_New() statement with no
argument only "declares" a pointer but does not allocate any
memory for the data it will eventually point to. Only if you want
to replace the data in a structure element, then you need to free
the pointer beforehand:
;; Replace data of first structure
IF Ptr_Valid(periodcube.freq) THEN Ptr_Free,
periodcube.freq
periodcube.freq = Ptr_New( DIndgen(200)*0.1 )
Hope this will clear your mind,
Martin
PS:
> "Never fight an inanimate object." - P. J. O'Rourke
No, it's far better to write them ;-)
--
[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[
[[ Dr. Martin Schultz Max-Planck-Institut fuer Meteorologie
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[[ Bundesstr. 55, 20146 Hamburg
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[[ phone: +49 40 41173-308
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[[ fax: +49 40 41173-298
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[[ martin.schultz@dkrz.de
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