Hi:
See inline...
On Tue, Jul 6, 2010 at 12:13 AM, McLovin <dave_dec...@hotmail.com> 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
>
> fm <- y ~ 1 + 2
> class(fm)
[1] "formula"
# Let's investigate the fm object a little further...
> str(fm)
Class 'formula' length 3 y ~ 1 + 2
..- attr(*, ".Environment")=<environment: R_GlobalEnv>
> fm[1]
`~`()
> fm[2]
y()
> fm[3]
1 + 2()
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.
>
True, but...
> sapply(fm, class)
[1] "name" "name" "call"
so the classes of the components of the formula are not the same.
An array requires that each element of the array have the same class.
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
>
You're trying to assign a three-element object to a single subscript
of a matrix - R is (correctly) telling you that doesn't compute.
>
> My question is: is it possible to assign formulas within a matrix or
> array?
If so, how? thanks....@real.com
>
I think you might have better luck trying to assign formulas to list
components,
since the classes of the components of a formula are not the same. For
this reason, you can't cram them into arrays or matrices for the reason
given above.
HTH,
Dennis
> --
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> http://r.789695.n4.nabble.com/Assign-Formulas-to-Arrays-or-Matrices-tp2279136p2279136.html
> Sent from the R help mailing list archive at Nabble.com.
>
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