R help - Mar 2010 - accessing info in object slots from listed objects using loops

Hey,

I have stacked a couple of garchFit objects in a list with names $fit1,
$fit2, ..., $fiti assigning objects names using a loop, i.e. after running
the loop modelStack = list($fit1, $fit2,...,$fiti).

Thus the following apply;
a = modelStack$fit2, then a is the second garchFit object of formal class
'fGarch' with 11 slots, @call, @formula... etc.

I then want to extract information in the 11 slots using another for loop,
say i want to access the slot a at fit$coef. In order for this to happen I need
to combine modelStack$fit2, where the $fit2 object name must be constructed
in the loop, with the slot name @fit$coef.

In order to construct the proper list names one could use the following in
the for loop;
name =
paste("modelStack$fit",i,"@fit$coef",sep="")  #
"modelStack$fit2 at fit$coef" for i = 2, 

and then use something like 
get(name) 

But this returns; Error in get(name) : object 'modelStack$fit2 at
fit$coef' not
found

If I just type modelStack$fit2 at fit$coef in the command window it returns the
proper info from the object list. I figure this is because R somehow
interpret "$" and "@" in get() differently than $ and @ as
"list
separators".

Does anyone know how to extract information in slots of listed objects using
a loop and on the run generated variable/object names?

JT

sample code
	nAssets = length(modelStack)

	for(i in 1:nAssets){
		name =
paste("modelStack[",i,"]@name$series$h",sep="")
		a = get(name)
                      t = length(a)
	} # end for loop

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Try this:

sapply(modelStack, slot, 'fit')['coef',]

On Wed, Mar 17, 2010 at 7:11 AM, torgrims <torgrims at stud.ntnu.no>
wrote:
>
> Hey,
>
> I have stacked a couple of garchFit objects in a list with names $fit1,
> $fit2, ..., $fiti assigning objects names using a loop, i.e. after running
> the loop modelStack = list($fit1, $fit2,...,$fiti).
>
> Thus the following apply;
> a = modelStack$fit2, then a is the second garchFit object of formal class
> 'fGarch' with 11 slots, @call, @formula... etc.
>
> I then want to extract information in the 11 slots using another for loop,
> say i want to access the slot a at fit$coef. In order for this to happen I
need
> to combine modelStack$fit2, where the $fit2 object name must be constructed
> in the loop, with the slot name @fit$coef.
>
> In order to construct the proper list names one could use the following in
> the for loop;
> name =
paste("modelStack$fit",i,"@fit$coef",sep="") ?#
> "modelStack$fit2 at fit$coef" for i = 2,
>
> and then use something like
> get(name)
>
> But this returns; Error in get(name) : object 'modelStack$fit2 at
fit$coef' not
> found
>
> If I just type modelStack$fit2 at fit$coef in the command window it returns
the
> proper info from the object list. I figure this is because R somehow
> interpret "$" and "@" in get() differently than $ and @
as "list
> separators".
>
> Does anyone know how to extract information in slots of listed objects
using
> a loop and on the run generated variable/object names?
>
> JT
>
> sample code
> ? ? ? ?nAssets = length(modelStack)
>
> ? ? ? ?for(i in 1:nAssets){
> ? ? ? ? ? ? ? ?name =
paste("modelStack[",i,"]@name$series$h",sep="")
> ? ? ? ? ? ? ? ?a = get(name)
> ? ? ? ? ? ? ? ? ? ? ?t = length(a)
> ? ? ? ?} # end for loop
>
> --
> View this message in context:
http://n4.nabble.com/accessing-info-in-object-slots-from-listed-objects-using-loops-tp1596135p1596135.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O