R help - Oct 2011 - setMethod "[" - extract by names within Slot

Hi R-helper!

I have problem with setMethods for "[". Here is example :

setClass("myClass", representation(ID.r = "numeric", ID.c =
"character", DAT = "matrix"))

to.myClass <- function(ID.r, ID.c, DAT) {
    out <- new("myClass", ID.r = ID.r, ID.c = ID.c, DAT = DAT)
    return(out)
      }
      
setMethod("[", "myClass", function(x, i, j, drop) {
    x@ID.r <- x@ID.r[i]
    x@ID.c <- x@ID.c[j]
    out.0 <- x@DAT[i,j]
    out.1 <- to.myClass(x@ID.r, x@ID.c, as.matrix(out.0))
    return(out.1)
  })

a <- to.myClass(seq(1,25),
c("A","A","B","B"), matrix(rnorm(100),
nrow = 25))
a


a[1:20, ] #works
a[, 1:3] #works
a[1:10, 1:3] #works

a[, "A"] #not works

What is solution to write "[" methods for extraction by names of Slot
"ID.c"

Thanks all. OV

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On 10/22/2011 02:11 AM, Omphalodes Verna wrote:
> Hi R-helper!
>
> I have problem with setMethods for "[". Here is example :
>
> setClass("myClass", representation(ID.r = "numeric",
ID.c = "character", DAT = "matrix"))
>
> to.myClass<- function(ID.r, ID.c, DAT) {
>      out<- new("myClass", ID.r = ID.r, ID.c = ID.c, DAT = DAT)
>      return(out)
>        }
>
> setMethod("[", "myClass", function(x, i, j, drop) {
>      x at ID.r<- x at ID.r[i]
>      x at ID.c<- x at ID.c[j]
>      out.0<- x at DAT[i,j]
>      out.1<- to.myClass(x at ID.r, x at ID.c, as.matrix(out.0))
>      return(out.1)
>    })
>
> a<- to.myClass(seq(1,25),
c("A","A","B","B"), matrix(rnorm(100),
nrow = 25))
> a
>
>
> a[1:20, ] #works
> a[, 1:3] #works
> a[1:10, 1:3] #works
>
> a[, "A"] #not works
thinking about your code, this is the same as

 >   ID.c = c("A","A","B","B")
 >   j = "A"
 >   ID.c[j]
[1] NA

>
> What is solution to write "[" methods for extraction by names of
Slot "ID.c"
Maybe (untested)

   setMethod("[", c("myClass", "ANY",
"character"),
       function(x, i, j, ..., drop=TRUE) {
           j = match(j, x at ID.c)
           x[i, j, ..., drop=TRUE]
      })
>
> Thanks all. OV
>
> 	[[alternative HTML version deleted]]
>
>
>
>
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