On 06/04/2011 03:07 AM, soeren.vo...@uzh.ch wrote:
Hello, an S4 class "Foo" is defined with a setter, $. For several reasons, the
setter calls a function, .foo.update(). However, bypassing the argument names of the
setter does not work. Question 1: Why not and how can I fix this? Question 2: What is the
way to define either the function or the setter to modify the original object (not
returning the modified copy of it an overwrite the original by assignment)? Thanks, Sören
setClass("Foo",
representation(
N = "numeric"
),
prototype(
N = 10000
)
)
.foo.update<- function(object, ...) {
args<- list(...)
for (i in slotNames("Foo")[pmatch(names(args), slotNames("Foo"),
nomatch=0)]) {
slot(object, i)<- args[[i]]
# indeed more to do here
return(object)
}
}
Since names(args) is 'name', and 'name' is not a slot of 'Foo', the
return of pmatch is 0 and .foo.update returns NULL. Put return(object)
outside the for loop.
setReplaceMethod("$", "Foo",
function(x, name, value) {
x<- .foo.update(x, name=value)
here your intention is that name=value to be substituted with N=99, but
you end up with name=99. You could arrange to parse this correctly, but
this isn't usually what you _want_ to do and I don't really understand
what you're trying to accomplish. Maybe
.foo.update <- function(object, name, value, ...)
{
slot(object, name) <- value
## some other stuff
object
}
Hope that helps a bit.
Martin
x
}
)
x<- new("Foo")
x
x$N<- 99
x # NULL????
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
--
Computational Biology
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N. PO Box 19024 Seattle, WA 98109
Location: M1-B861
Telephone: 206 667-2793
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
