Is this a bug? We define the [ operator for class test. All it does is force drop to be FALSE and then calls the NextMethod. If we specify drop= in the call then it works as expected (### 2 and ### 3) but if we do not specify drop (### 1) then it acts as if drop=TRUE even though we have set it to FALSE within [.test .> "[.test" <- function(x, i, j, drop = TRUE) {+ drop <- FALSE + NextMethod("[") + }> x <- structure(matrix(1:12, 4, 3), class = "test")> x[1,] ### 1 - why does it ignore drop=FALSE in [.test ????[1] 1 5 9> x[1,,drop = TRUE] ### 2 - ok[,1] [,2] [,3] [1,] 1 5 9> x[1,,drop = FALSE] ### 3 - ok[,1] [,2] [,3] [1,] 1 5 9> R.version.string # windows XP[1] "R version 2.0.0, 2004-10-04"
Gabor Grothendieck wrote:> > Is this a bug? We define the [ operator for class test. > All it does is force drop to be FALSE and then calls > the NextMethod. If we specify drop= in the call then > it works as expected (### 2 and ### 3) but if we do not > specify drop (### 1) then it acts as if drop=TRUE > even though we have set it to FALSE within [.test . > > >>"[.test" <- function(x, i, j, drop = TRUE) { > > + drop <- FALSE > + NextMethod("[") > + } > >>x <- structure(matrix(1:12, 4, 3), class = "test") > > >>x[1,] ### 1 - why does it ignore drop=FALSE in [.test ???? > > [1] 1 5 9 > > >>x[1,,drop = TRUE] ### 2 - ok > > [,1] [,2] [,3] > [1,] 1 5 9 > >>x[1,,drop = FALSE] ### 3 - ok > > [,1] [,2] [,3] > [1,] 1 5 9 > >>R.version.string # windows XP > > [1] "R version 2.0.0, 2004-10-04" >Well, the *arguments* of the encolsing function are taken, but not the objects defined therein. What you can do is: "[.test" <- function(x, i, j, drop = TRUE) { NextMethod("[", drop = FALSE) } Uwe Ligges
Uwe Ligges <ligges@statistik.uni-dortmund.de> wrote:
:
: Gabor Grothendieck wrote:
:
: >
: > Is this a bug? We define the [ operator for class test.
: > All it does is force drop to be FALSE and then calls
: > the NextMethod. If we specify drop= in the call then
: > it works as expected (### 2 and ### 3) but if we do not
: > specify drop (### 1) then it acts as if drop=TRUE
: > even though we have set it to FALSE within [.test .
: >
: >
: >>"[.test" <- function(x, i, j, drop = TRUE) {
: >
: > + drop <- FALSE
: > + NextMethod("[")
: > + }
: >
: >>x <- structure(matrix(1:12, 4, 3), class = "test")
: >
: >
: >>x[1,] ### 1 - why does it ignore drop=FALSE in [.test ????
: >
: > [1] 1 5 9
: >
: >
: >>x[1,,drop = TRUE] ### 2 - ok
: >
: > [,1] [,2] [,3]
: > [1,] 1 5 9
: >
: >>x[1,,drop = FALSE] ### 3 - ok
: >
: > [,1] [,2] [,3]
: > [1,] 1 5 9
: >
: >>R.version.string # windows XP
: >
: > [1] "R version 2.0.0, 2004-10-04"
: >
:
:
: Well, the *arguments* of the encolsing function are taken, but not the
: objects defined therein. What you can do is:
:
: "[.test" <- function(x, i, j, drop = TRUE) {
: NextMethod("[", drop = FALSE)
: }
:
: Uwe Ligges
Thanks. That worked. Is that a workaround or is it a bug?
Note that if I set both i and drop within the [.test method then
the modified i gets passed but the modified drop does not:
R> "[.test" <- function(x, i, j, drop = TRUE) {
+ i <- 2; drop <- FALSE
+ NextMethod("[")
+ }
R> x <- structure(matrix(1:12, 4, 3), class = "test")
R> x[1,]
[1] 2 6 10