Strange behavior of assign in a S4 method.
Dear Wolfgang, Thanks for the showMethod and the link.
Perhaps juggling with the 'n' argument of 'parent.frame' could help in hacking something together that 'works'
I just change the argument list of foo2 to perfectly match with the definition.
but as far as I can see what you want to is an abuse of R's pass by value / functional language semantics.
Yes I kown. When I learnt object programming, one of the basic was that some methods was design to change internals value of the fields. It is what I try to do here.
For example, try these and check whether this results in what you intended: foo2(3) foo2(e+2) sapply(1:5, foo2) ls()
This will not apply, because I my case, the function foo2 is avalable
only for object of class FooClass and the only possible use will be :
toto <- new("FooClass")
....
foo2(toto)
Best wishes
Christophe
Best wishes
Wolfgang
Christophe Genolini scripsit 15/03/10 11:33:
Hi the list,
I define a method that want to change an object without assignation
(foo(x) and not x<-foo(x)) using deparse and assign.
But when the argument of the method does not match *exactly* with the
definition of the generic function, assign does not work...
Anything wrong?
Christophe
#------ Does not work ------#
setGeneric("foo1",function(x,...){standardGeneric("foo1")})
setMethod(f="foo1",signature="numeric",definition=
function(x,y=1,...){
nameX<-deparse(substitute(x))
x <- x^2
assign(nameX,x,envir=parent.frame())
}
)
e <- 3
foo1(e,y=5)
cat(e)
#------ Does work ------#
setGeneric("foo2",function(x,...){standardGeneric("foo2")})
setMethod(f="foo2",signature="numeric",definition=
function(x,...){
nameX<-deparse(substitute(x))
x <- x^2
assign(nameX,x,envir=parent.frame())
}
)
e <- 3
foo2(e,y=5)
cat(e)
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