R help - Feb 2007 - matrix of matrices

Dear all,

it is likely a stupid question but I cannot solve it.

I want to have a matrix of 100 elements.
Each element must be a vector of 500 elements.

If I do:
    imp<-array(dim=100)
    imp[1]<-vector(length=500)
it does not work. Warning message: "number of items to replace is not a
multiple of replacement length"

If I do:
    imp <- array(dim=c(100,500))   
and then fill imp:
    for(i in c(1:500)) {
        imp[i,] <- im[1:500,]
        #im[1:500,] is a vector of length 500, of class numeric. IT
CONTAINS NAMES!
    }

Now it works, but I loose the labels (names) associated to the original
"im" variable.
If I just do:
    j<- im[1:500,]
I do not loose the labels.

names(j) => list of labels
names(imp[1,]) => NULL

Any clue?

Thanks in advance!
Federico

For the case someone is interested in it, here it is the solution
somebody suggested me: to use a list.

imp <- vector("list", 100)
imp[[1]] <- im[1:500,]
names(imp[[1]]) => the list of labels of imp[1:500,]

Thanks!
Federico



Federico Abascal wrote:
> Dear all,
>
> it is likely a stupid question but I cannot solve it.
>
> I want to have a matrix of 100 elements.
> Each element must be a vector of 500 elements.
>
> If I do:
>     imp<-array(dim=100)
>     imp[1]<-vector(length=500)
> it does not work. Warning message: "number of items to replace is not
a
> multiple of replacement length"
>
> If I do:
>     imp <- array(dim=c(100,500))   
> and then fill imp:
>     for(i in c(1:500)) {
>         imp[i,] <- im[1:500,]
>         #im[1:500,] is a vector of length 500, of class numeric. IT
> CONTAINS NAMES!
>     }
>
> Now it works, but I loose the labels (names) associated to the original
> "im" variable.
> If I just do:
>     j<- im[1:500,]
> I do not loose the labels.
>
> names(j) => list of labels
> names(imp[1,]) => NULL
>
> Any clue?
>
> Thanks in advance!
> Federico
>
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