R help - Nov 2010 - Pass character vector to function argument

A bit embarrassed to post this seemingly trivial question, but I can't find
anything in the archive that's quite relevant:

a1=1
a2=2

obs=objects(pattern=glob2rx("a?"))

I want to utilize 'obs' as a function argument to produce something
like:

sum(a1,a2)

Obviously, sum(obs) doesn't work, but I've tried variations of
'eval', 'parse', 'mget', and 'noquote' without
success. What am I missing?

Thanks,
Kevin



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On Nov 16, 2010, at 10:34 AM, Kevin Ummel wrote:
> A bit embarrassed to post this seemingly trivial question, but I  
> can't find anything in the archive that's quite relevant:
>
> a1=1
> a2=2
>
> obs=objects(pattern=glob2rx("a?"))
>
> I want to utilize 'obs' as a function argument to produce something
> like:
>
> sum(a1,a2)
>
?get
 > sum(sapply(obs, get))
[1] 3

> Obviously, sum(obs) doesn't work, but I've tried variations of  
> 'eval', 'parse', 'mget', and 'noquote'
without success. What am I
> missing?
>
> Thanks,
> Kevin
>
-- 
David Winsemius, MD
West Hartford, CT

Hi,

It would have been nice to see what you've tried.

Here is what I got (maybe not the easiest, but looks like it works)
a1 <- 1
a2 <- 2
obs <- objects(pattern=glob2rx("a?"))
sum(unlist(mget(obs, envir=.GlobalEnv)))
[1] 3

It also works with vectors:
a1 <- 1:10
a2 <- 11:20
sum(unlist(mget(obs, envir=.GlobalEnv)))
[1] 210

Is it what you're looking for?

HTH,
Ivan



Le 11/16/2010 16:34, Kevin Ummel a ?crit :
> A bit embarrassed to post this seemingly trivial question, but I can't
find anything in the archive that's quite relevant:
>
> a1=1
> a2=2
>
> obs=objects(pattern=glob2rx("a?"))
>
> I want to utilize 'obs' as a function argument to produce something
like:
>
> sum(a1,a2)
>
> Obviously, sum(obs) doesn't work, but I've tried variations of
'eval', 'parse', 'mget', and 'noquote' without
success. What am I missing?
>
> Thanks,
> Kevin
>
>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
-- 
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. S?ugetiere
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calandra at uni-hamburg.de

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