Message-ID: <alpine.LFD.2.00.0903261055130.2933@nokomis.stat.uiowa.edu>
Date: 2009-03-26T15:57:21Z
From: Luke Tierney
Subject: programming creating different functions in a loop
In-Reply-To: <20090326161747.2455d1a8@mgf.econ.gu.se>
for() does not creae separete bindings for the index each iteration,
so the function bodies see the global binding of i, which in this case
will be the final value. One possible solution is to use local(), e.g.
for(i in 1:3){
assign(paste("f",i,sep=""),
local({
k <- i # create local binding with current loop index value
function(x) x + k
}))
}
luke
On Thu, 26 Mar 2009, Florin Maican wrote:
> 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
>
>
--
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa Phone: 319-335-3386
Department of Statistics and Fax: 319-335-3017
Actuarial Science
241 Schaeffer Hall email: luke at stat.uiowa.edu
Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu