Displaying 20 results from an estimated 3000 matches similar to: "the difference between UseMethod and NextMehod?"
2012 Dec 04
1
inconsistencies between ?class and ?UseMethod
Hi,
The 2 man pages give inconsistent description of class():
Found in ?class:
If the object does not have a class attribute, it has an implicit
class, ?"matrix"?, ?"array"? or the result of ?mode(x)? (except
that integer vectors have implicit class ?"integer"?).
Found in ?UseMethod:
Matrices and arrays have class ?"matrix"?
1999 Apr 14
5
R's UseMethod() does not dispatch on changed class() (PR#167)
(opening new bug report thread, on suggestion of BDR ..)
I said on vaguely related topic:
MM> There's another long-standing
MM> UseMethod / NextMethod / Dispatch problem that I've never traced/solved..
MM>
MM> Look at the $RHOME/tests/mode-methods.R file !
Peter Dalgaard already remarked :
PD> ..i.e. this:
PD> abc <- function(x, ...) {
PD> if
2006 Apr 14
3
The object argument of NextMethod.
My question is when the object argument of NexthMethod be used?
In the following example, weather object argument is used will not
affects the result.
###
foo=function(x) {UseMethod("foo")}
foo.cls1=function(x)
{
x=x+1;class(x)<-"ncls"
NextMethod()
}
foo.ncls=function(x)
{
cat("ncls\n")
}
foo.cls2=function(x)
{
cat("cls2\n");print(x)
}
1999 Apr 16
1
NextMethod
>> One clear moral seems to be don't do anything more inside a
>> generic function than you really need to do. Keep it *very*
>> simple indeed.
>>
> I recall JMC saying something like, all generic functions
> should be one line long; a call to the appropriate UseMethod.
It certainly is encouraging to know that others also have been confused by
aspects of
2012 Oct 17
1
Do *not* pass '...' to NextMethod() - it'll do it for you; missing documentation, a bug or just me?
Hi,
although I've done S3 dispatching for more than a decade now, I think
I managed to overlook/avoid the following pitfall when using
NextMethod():
If you explicitly pass argument '...' to NextMethod(), you will
effectively pass those argument twice to the "next" method!
EXAMPLE:
foo0 <- function(...) UseMethod("foo0");
foo1 <- function(...)
2019 Aug 07
1
NextMethod() and argument laziness
Hi all, I'd like to ask if the following behavior is a bug. To me it
certainly feels surprising, at the very least. In this example, I would
like to call NextMethod() from my `child` object, have `cols` be left
untouched, and then substitute(cols) in the parent method. It works when
you use a `parent` object (as expected), but I would have also expected to
get `mpg` back when calling it from
2004 Oct 28
1
Another problem with next method
I have another problem with NextMethod. Not sure if its related
to the last problem.
In this example, we have a generic called ff with methods
for AsIs and test classes. We call the generic with an
object of AsIs class. The corresponding method adds 1 to it
and then changes the class to test followed by issuing a
NextMethod. However, that results in this error (using R
2.0.0, 2004-10-04
2010 Jul 22
1
class
Hello,
### I created two classes "A" and "B". "A" is the superclass of "B".
setClass("A", representation(s1="numeric"),prototype=prototype(s1=8))
setClass("B",contains="A",representation(s2="character"),prototype=list(s2="hi"))
myA=new("A")
myB=new("B")
#### I created
2010 Feb 14
1
NextMethod() example from S Programming by Venables and Ripley (page 78)
S Programming by Venables and Ripley (page 78) has the example listed
at the end of this email. However, I get the following error when I
try the example. I don't understand the descriptions of NextMethod on
its help page. Could somebody let me know how to fix the error of this
example?
> test(x)
c1
c2
Error in NextMethod() : no method to invoke
Calls: test -> test.c1 -> NextMethod
2003 Feb 13
3
OO programming in R
Dear,
I'm looking for some examples on OO programming in R. I have the
programming manual with explanation on UseMethod and NextMethod but I
miss some practical examples to get me going (I hope). I searched the
web but could not find a good independent tutorial on this.
Any suggestions are welcome,
Kris
--
------------------------------------------------------------------------
2003 Oct 02
1
"[[<-","[[" default?
Hi!
I have implemented class specific behaviour of "[[<-.myclass"<-function().
How it is posible to call the "[[.default" on an object of myclass?
Eryk
Dipl. bio-chem. Eryk Witold Wolski @ MPI-MG Dep. Vertebrate Genomics
Ihnestrasse 73 14195 Berlin 'v'
tel: 0049-30-84131285 / \
mail: wolski@molgen.mpg.de ---W-W----
2019 May 14
2
[R-pkg-devel] Three-argument S3method declaration does not seem to affect dispatching from inside the package.
On Tue, 14 May 2019 at 12:31, Pavel Krivitsky <pavel at uow.edu.au> wrote:
>
> > Note that disabling name-based dispatch implies two things: 1) the
> > inability to override your method by defining gen.formula in the
> > global environment, and 2) another package can break yours (i.e.,
> > internal calls to gen()) by registering an S3 method for gen() after
>
2010 Apr 27
1
suggestion on method dispatch
Dear all, I have define a function and its methods as follows:
######## beginning of code
fn <- function(x,...){
UseMethod("fn")
}
fn.foo1 <- function(x, commonA=1, ...){
print("fn.foo1 is called.")
}
fn.foo2 <- function(x, uniqueFoo2, common=1, ...){
## uniqueFoo2 is a unique argument in fn.foo2
x <- uniqueFoo2; class(x) <- "foo1"
## use uniqueFoo2
2004 Nov 15
1
UseMethod call with no arguments
Dear R developers,
I will ask a very straightforward question concerning UseMethod's future,
because people depending on my code wonder what will happen to it next.
In R v2.0.1 NEWS it says
o The undocumented use of UseMethod() with no argument is now
formally deprecated.
and in the R v2.0.1 help(UseMethod) it says
'UseMethod' accepts a call with no arguments and tries to
2019 May 19
2
[R-pkg-devel] Three-argument S3method declaration does not seem to affect dispatching from inside the package.
On Sat, 18 May 2019 at 23:34, Pavel Krivitsky <pavel at uow.edu.au> wrote:
>
> > The issue here is that you are registering a non-standard name
> > (.gen.formula) for that generic and then defining what would be the
> > standard name (gen.formula) for... what purpose? IMHO, this is a bad
> > practice and should be avoided.
>
> The situation initially arose
2001 Nov 16
1
UseMethod() fails to (PR#1176)
match the argument 'x' if there is another argument with prefix 'x'
Full_Name: Henrik Bengtsson
Version: 1.3.1
OS: Sun Solaris 8
Submission from: (NULL) (130.235.3.49)
I ran into a strange problem with UseMethod(). Run the following code:
foo.Bar <- function(this, x=0, xidx=0) {
cat("In foo.Bar(): ", this, ", x=", x, ", xidx=", xidx,
2006 May 19
1
UseMethod infelicity
If I do
> example(lm)
...
> mycoef <- function(object, ...) UseMethod("coef", object)
> mycoef(lm.D9)
Error in mycoef(lm.D9) : no applicable method for "coef"
which is pretty surprising, as coef has a default method.
After a bit of digging, this comes from do_usemethod having
defenv = environment where the generic was defined */
defenv =
2019 Oct 09
2
S3 lookup rules changed in R 3.6.1
tl;dr: S3 lookup no longer works in custom non-namespace environments as of
R 3.6.1. Is this a bug?
I am implementing S3 dispatch for generic methods in environments that are
not
packages. I am trying to emulate the R package namespace mechanism by
having a
?namespace? environment that defines generics and methods, but only exposes
the
generics themselves, not the methods.
To make S3 lookup work
2023 Jul 08
1
Getting an error calling MASS::boxcox in a function
Thanks John.
?boxcox says:
*************************
Arguments
object
a formula or fitted model object. Currently only lm and aov objects are handled.
*************************
I read that as saying that
boxcox(lm(z+1 ~ 1),...)
should run without error. But it didn't. And perhaps here's why:
BoxCoxLambda <- function(z){
b <- MASS:::boxcox.lm(lm(z+1 ~ 1), lambda = seq(-5, 5,
2001 Dec 11
4
crash bug in get("function.name")() (PR#1211)
R : Copyright 2001, The R Development Core Team
Version 1.3.1 (2001-08-31)
> tmp <- factor(1:3)
> get("print.factor")(tmp)
[1] 1 2 3
Levels: 1 2 3
> print.a <- function(x,...) {
+ print("this is a")
+ NextMethod("print", x, quote = FALSE, right = TRUE, ...)
+ }
>
> get("print.a")
function(x,...) {
print("this is a")