| Smart way to extract the same attribute from a list of objects? [message #81560] |
Thu, 04 October 2012 08:44  |
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Paul Van Delst[1]
Messages: 1157
Registered: April 2002
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Senior Member |
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Hello,
I have a list,
IDL> help, r
R LIST <ID=2 NELEMENTS=616>
composed of only a single type of object,
IDL> help, r[0]
<Expression> OBJREF = <ObjHeapVar3(RTSOLUTION)>
IDL> help, r[200]
<Expression> OBJREF = <ObjHeapVar1803(RTSOLUTION)>
..etc..
What I want to do is extract the same attribute from every object in the
list.
The way I'm doing it now is:
radiance = DBLARR(r.Count())
FOR i=0,r.count()-1 DO BEGIN
r[i].get_property, radiance=x
radiance[i]=x
ENDFOR
and then I can do stuff with "radiance", such as plot it.
I find the above a little bit clunky since I have to explicitly iterate
through the list to pull out what I want, creating the temporary
"holding" array beforehand. If I want to extract more than one thing I
end up with something like
n = r.Count()
channel = LONARR(n)
radiance = DBLARR(n)
FOR i=0,n-1 DO BEGIN
r[i].get_property, radiance=x, channel=j
radiance[i]= x
channel[i] = j
ENDFOR
which just looks messy.
Does anyone have any better/faster/more-elegant solutions to this sort
of problem?
I've had a look at the _overloadBracketsRightSide function documentation
but, to be honest, the description seems rather impenetrable to me. I
guess I'm looking for something akin to the "ELEMENTAL" attribute in
Fortran where a procedure written for in/output scalars can also operate
on any rank arrays (as long as they are conformable.)
cheers,
paulv
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