[R-pkg-devel] Exporting S3 methods for base generics
Hi Charles,
if a generic exists already in the base, you only have to export the actual
S3 method. Your problem is that base::pmax() is not a generic S3 function.
So R gives you the correct warning: the S3 generic in your package will
always mask the base pmax function. And that's not really a problem,
especially since you ensured the base functionality with your default
method.
If you want to avoid that warning, use S4.
#' @rdname
setGeneric("pmax")
#' @rdname pmax
#' @method pmax myclass
#' @export
setMethod("pmax",
"myclass",
function(...){
# do some stuff
})
More information on how to deal with dots can be found on the help page
?dotsMethods.
If you have a generic in the base package (eg plot is such one), you only
define the method and use:
#' @export
plot.myclass <- function(x, y, ...){
# do some more stuff
}
Cheers
Joris
On Mon, Jun 26, 2017 at 6:28 PM, Charles Determan <cdetermanjr at gmail.com>
wrote:
Greetings R users,
I was wondering how others are exporting S3 methods in their packages when
the generic is in 'base'. For example, let's say I want to export a new
pmax method. The only way I have found to get this to work is by
redefining the function with 'UseMethod' and setting the default method.
#' @export
pmax <- function(...){ UseMethod("pmax") }
#' @export
pmax.default <- function(..., na.rm=FALSE){ base::pmax(..., na.rm=FALSE) }
setClass("myclass")
#' @export
pmax.myclass <- function(..., na.rm = FALSE){
print('myclass pmax!')
}
Although this works, I get the 'warning'
The following objects are masked from 'package:base':
pmax
I would like the package build and loading to be as clean as possible but
if this is acceptable and not considered a problem I will let it go. It
just seems odd that one would to redefine a the generic when in states in
the docs for 'pmax' that it will also work on classed S3 objects but
perhaps I am reading this incorrectly.
Thanks,
Charles
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Joris Meys Statistical consultant Ghent University Faculty of Bioscience Engineering Department of Mathematical Modelling, Statistics and Bio-Informatics tel : +32 9 264 59 87 Joris.Meys at Ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php [[alternative HTML version deleted]]