R help - Jun 2004 - apply/looping query

I have several large matrices each having perhaps one or two
data points missing. For instance one point in 2881 is missing. As I want to
perform
various analyses on these matrices I feel it is not
unreasonable to linearly interpolate over the missing points. I want to
basically "fill in
the gaps" of the original matrix - the following piece of code
doesn't work and i'm not sure where i'm going wrong:

x=1:2881
my.new.matrix<-matrix(nrow=2881,ncol=20)
for(i in 1:20){
my.new.matrix[[i]]<-approx(x,my.matrix[,i],n=2881)
}

the error message says:

Error: more elements supplied than there are to replace

where am I going wrong??

Thanks in advance..
Laura

Laura Quinn wrote:
> x=1:2881
> my.new.matrix<-matrix(nrow=2881,ncol=20)
> for(i in 1:20){
> my.new.matrix[[i]]<-approx(x,my.matrix[,i],n=2881)
> }
> 
> the error message says:
> 
> Error: more elements supplied than there are to replace
> 
> where am I going wrong??
approx() returns a list with $x and $y components

I'd use [,x] instead of [[i]] to replace columns.

Hence:

  for(i in 1:20){
   my.new.matrix[,i]<-approx(x,my.matrix[,i],n=2881)$y
  }

Baz