I would like to create a function to convert data based on a class using
as.numeric
Similarly, using a plot, I do:
plot.essai <- function(x, ...) {return(x*2)}
d <- 10
class(d) <- "essai"
plot(d)
It works:
[1] 20
attr(,"class")
[1] "essai"
Now same with as.numeric:
as.numeric.essai <- function(x, ...) {return(x*2)}
as.numeric(d)
It does not work:
[1] 10
Is it possible ?
Thanks a lot
Marc Girondot
Hello,
Actually, it's working as expected. 'numeric' is a class and the
function as.numeric() is doing what it should:
as.numeric.essai <- function(x, ...) {return(x*2)}
d2 <- as.numeric(d)
class(d2)
[1] "numeric"
Maybe you want an as.essai function.
as.essai <- function(x, ...) {x <- as.numeric(x); class(x) <-
"essai"; x*2}
as.essai(d)
[1] 20
attr(,"class")
[1] "essai"
I also think you're making a confusion about what the functions do. They
coerce to a class, they don't do that sort of arithmetics.
Hope this helps,
Rui Barradas
Em 16-11-2012 10:01, Marc Girondot escreveu:> I would like to create a function to convert data based on a class
> using as.numeric
>
> Similarly, using a plot, I do:
> plot.essai <- function(x, ...) {return(x*2)}
> d <- 10
> class(d) <- "essai"
>
> plot(d)
>
> It works:
>
> [1] 20
> attr(,"class")
> [1] "essai"
>
> Now same with as.numeric:
> as.numeric.essai <- function(x, ...) {return(x*2)}
> as.numeric(d)
>
> It does not work:
>
> [1] 10
>
> Is it possible ?
>
> Thanks a lot
> Marc Girondot
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
On 16/11/2012 10:01, Marc Girondot wrote:> I would like to create a function to convert data based on a class using > as.numeric > > Similarly, using a plot, I do: > plot.essai <- function(x, ...) {return(x*2)} > d <- 10 > class(d) <- "essai" > > plot(d) > > It works: > > [1] 20 > attr(,"class") > [1] "essai" > > Now same with as.numeric: > as.numeric.essai <- function(x, ...) {return(x*2)} > as.numeric(d)You need to read the help (as the posting guide asked you to do before posting): ?as.numeric? is a generic function, but S3 methods must be written for ?as.double?. It is identical to ?as.double? (and ?as.real?). The rest of the help page makes clear why using 'numeric' will confuse others as well as confusing yourself.> It does not work: > > [1] 10 > > Is it possible ? > > Thanks a lot > Marc Girondot > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.-- Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595