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 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

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

Thanks all. OV

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