[R] programming creating different functions in a loop
Bert Gunter
gunter.berton at gene.com
Thu Mar 26 17:33:09 CET 2009
... but perhaps even more straightforward is:
f <- function(i,x)x+i
Of course, we don't know exactly what the poster is after with his rather
arcane construction, so this may not suit. But you know the rule: if the
question requires a complex, tricky answer, it's probably the wrong
question.
Cheers,
Bert
Bert Gunter
Genentech Nonclinical Biostatistics
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of Greg Snow
Sent: Thursday, March 26, 2009 9:25 AM
To: Florin Maican; r-help at r-project.org
Subject: Re: [R] programming creating different functions in a loop
Anytime that you are tempted to use assign and a loop, you should consider
using lapply (or sapply) and a list instead.
Consider this alternative:
> f <- lapply( 1:3, function(i){ force(i); function(x) x+i} )
>
> f[[1]](3)
[1] 4
> f[[2]](10)
[1] 12
> f[[3]](0)
[1] 3
>
> sapply( f, function(f) f(1:10) )
[,1] [,2] [,3]
[1,] 2 3 4
[2,] 3 4 5
[3,] 4 5 6
[4,] 5 6 7
[5,] 6 7 8
[6,] 7 8 9
[7,] 8 9 10
[8,] 9 10 11
[9,] 10 11 12
[10,] 11 12 13
Hope this helps,
--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Florin Maican
> Sent: Thursday, March 26, 2009 9:18 AM
> To: r-help at r-project.org
> Subject: [R] programming creating different functions in a loop
>
> Hi
>
> I want to create the following functions in a loop
>
> f1<-function(x){x+1}
> f2<-function(x){x+2}
> f3<-function(x){x+3}
>
> Output f1(2)=3
> f2(2)=4
> f3(2)=5
>
>
> I tried to create the in a loop as bellow but I get wrong on answers
> because the value of i change
>
> for(i in 1:3){
> assign(paste("f",i,sep="")
> ,function(x)
> x+i
> )
> } # end for
>
> Output f1(2)=5
> f2(2)=5
> f3(2)=5
> But it is not what I want. The question is how I can
> fix in R the value of "i" in my functions? I tried to use assign() and
> get(),but I did not manage.
>
> Thanks in advance,
> Florin
>
> --
> Florin Maican
> ==================================
>
> Department of Economics,
> School of Business, Economics and Law,
> Gothenburg University, Sweden
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> ------------------------------------
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> counted counts."
> --- Einstein ---
>
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