On 02/05/2011 02:58 PM, Bogaso Christofer wrote:
> Thanks Martin for your help. Although your suggestion is working for
> somewhat restrictive case, I would like to make thing more generic. For
> example:
>
> setMethod("Arith", c("Me", "Me"), function(e1, e2) callGeneric(e1@x1,
> e2@x1))
>
> with in (new1 + new2) is working perfectly, however if I want to add
> arbitrary number of objects then it fails:
>
>> new1 + new2 - new1
> Error in new1 + new2 - new1 : non-numeric argument to binary operator
as written, new1 + new2 returns a numeric, so (new1 + new2) - new1 would
require a method with signature c("numeric", "Me"). But perhaps what you
want is an implementation along the lines of
setMethod(Arith, c("Me", "Me"), function(e1, e2) {
new("Me", x1=callGeneric(e1@x1, e2@x2)
x2=c(e1@x2, e2@x2))
})
i.e., return an instance of "Me".
Martin
>
> What can I do to handle this?
>
> Thanks and regards,
>
>
> -----Original Message-----
> From: Martin Morgan [mailto:mtmor...@fhcrc.org]
> Sent: 06 February 2011 03:57
> To: Bogaso Christofer
> Cc: r-help@r-project.org
> Subject: Re: [R] Seeking help to define method for '+'
>
> On 02/05/2011 02:19 PM, Bogaso Christofer wrote:
>> Dear all, I am trying to define "+" method for my newly defined s4 class
>> which is as follows:
>>
>>
>>
>> setClass("Me", sealed=F,representation(x1 = "numeric", x2 = "character"))
>>
>> new1 <- new("Me", x1=2, x2="comment1")
>>
>> new2 <- new("Me", x1=3, x2="comment1")
>>
>>
>>
>> setMethod("+", "Me", definition=function(x,y) cat(x@x1 + y@x1, "\n"))
>>
>>
>>
>> However while am trying to set method, it fails:
>>
>> Error in conformMethod(signature, mnames, fnames, f, fdef, definition) :
>>
>> in method for '+' with signature 'e1="Me"': formal arguments (e1 = "Me",
>> e2 = "Me") omitted in the method definition cannot be in the signature
>
> From
>
>> getGeneric("+")
> standardGeneric for "+" defined from package "base"
> belonging to group(s): Arith
>
> function (e1, e2)
> standardGeneric("+", .Primitive("+"))
> <environment: 0x19a9918>
> Methods may be defined for arguments: e1, e2
> Use showMethods("+") for currently available ones.
>
> you can see that the generic is defined to dispatch on two arguments in
> a signature function(e1, e2). So
>
> setMethod("+", c("Me", "Me"), function(e1, e2) e1@x1 + e2@x1)
>
> but S4 also has group generics, and
>
> setMethod("Arith", c("Me", "Me"),
> function(e2, e2) callGeneric(e1@x1, e2@x1))
>
> will define not just + but also - and other functions in the 'Arith'
> group. See
>
> ?GroupGenericFunctions
>
> Martin
>
>>
>>
>>
>> I am just started learning s4 class system therefore please forgive me if
> I
>> have some any bad mistakes. Anyway I would really appreciate if someone
>> point me how should I proceed.
>>
>>
>>
>> Thanks and reagrds,
>>
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
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>> PLEASE do read the posting guide
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>> and provide commented, minimal, self-contained, reproducible code.
>
>
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