Dear List:

I am generating N datasets using the following

Sigma<-matrix(c(400,80,80,80,80,400,80,80,80,80,400,80,80,80,80,400),4,4
)
mu<-c(100,150,200,250)

N=100
for(i in 1:N) 
{ 
assign(paste("Data.", i, sep=''),
as.data.frame(cbind(seq(1:1000),(mvrnorm(n=1000, mu, Sigma)))))
} 

With these datasets, I need to work on some of the variables and then
run each dataset through a linear model. I am having some trouble
working with variables within the loop and wonder if anyone can offer
any pointers. 

The first thing I am trying to do is add 2 variables together that are
in each dataset. I am sure this is extremely trivial, but I can't seem
to get that to work.

I have tried:

for (i in 1:5){
assign(paste("x",i,sep=""),(get(paste("Data.",i,sep=""))[["V2"]])+(get(p
aste("Data.",i,sep=""))[["V2"]]))
}

Now, this code works, but I want for this vector to be a variable within
each dataframe. Outside the loop, the equivalent code would be

attach(Data.1)
Data.1$V6<-V1+V2
Detach(Data.1)

Another task I would like to perform is to reshape each dataframe for
longitudinal analysis. I have tried the following:

for (i in 1:5){
assign(paste("long",i,sep=""),reshape(paste("Data.",i,sep=""),idvar=get(
paste("Data.",i,sep="")[["V1"]]),
varying=list(names(get(paste("Data",i,sep="")[["V2"]]):get(paste("Data",
i,sep="")[["V5"]])),v.names="score",direction="long")
} 

This isn't working and I'm not sure if the code is even close. 

In general, performing all of these operations outside a loop for a
single dataframe is simple. My trouble is performing equivalent
operations within a loop. 

Thanks for any help offered.

Harold

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