[R] Method dispatch

[Martin Morgan]

On 03/01/2010 01:31 PM, Zhang,Yanwei wrote:
> Dear all,
> 
> In a package, I defined a method for "summary" using
setMethod(summary, signature="abc") for my class "abc", but when the
package is loaded, the function "summary(x)" where x is of class "abc"
seems to have called the default summary function for "ANY" class.
Shouldn't it call the method I have defined? How could I get around with
that? Thanks.

Hi Wayne -- It's hard to tell from what you've written, but this and
your earlier question on 'S4 issues' sounds like a NAMESPACE problem.
Are you using a name space? If so, provide additional detail. Also,
verify that you are only loading your package and not another, e.g., one
with a 'summary' generic that is being found before yours.

Probably your best bet is to simplify as much as possible -- I have a
single file in 'pkgA/R', with

  setClass("A", "numeric")
  setMethod("summary", "A", function(object, ...) "A")


> library(pkgA)
> summary(new("A"))
[1] "A"
> sessionInfo()
R version 2.10.1 Patched (2010-02-23 r51168)
x86_64-unknown-linux-gnu

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
 [5] LC_MONETARY=C              LC_MESSAGES=en_US.UTF-8
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
 [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] pkgA_1.0

Martin


> 
> 
> Wayne (Yanwei) Zhang
> Statistical Research
> CNA
> 
> 
> 
> 
> 
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-- 
Martin Morgan
Computational Biology / Fred Hutchinson Cancer Research Center
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