[R] Assign Formulas to Arrays or Matrices?

[Patrick Burns]

On 06/07/2010 08:13, McLovin wrote:
>
> Hi,
>
> I am very new to R.  I am hoping to create formulas and assign them to
> locations within an array (or matrix, if it will work).
>
> Here's a simplified example of what I'm trying to do:
>
> form.arr<- array(31,5,3)
> for (i in seq(from=1, to=31, by=1)) {
> 	for (j in seq(from=1, to=5, by=1)) {
> 		form.arr[i,j,]<- as.formula(y~1+2)
> 	}
> }
>
> which results in this error:
> Error in form.arr[i, j, ]<- as.formula(y ~ 1 + 2) :
>    incorrect number of subscripts
>
> The reason I had made the 3rd dimension of the array size 3 is because
> that's the length R tells me that formula is.
>
> When I had tried to do this using a matrix, using this code:
>
> form.mat<- matrix(31,5,3)
> for (i in seq(from=1, to=31, by=1)) {
> 	for (j in seq(from=1, to=5, by=1)) {
> 		form.mat[i,j] = as.formula(y~1+2)
> 	}
> }
>
> I was told:
>
> Error in form.mat[i, j] = as.formula(y ~ 1 + 2) :
>    number of items to replace is not a multiple of replacement length
>
> My question is: is it possible to assign formulas within a matrix or array?
> If so, how?  Thanks.not at real.com

You can create a matrix of mode list to do that.
An example is on page 39 of 'The R Inferno'.

-- 
Patrick Burns
pburns at pburns.seanet.com
http://www.burns-stat.com
(home of 'Some hints for the R beginner'
and 'The R Inferno')