> On Jun 27, 2018, at 3:58 PM, Achim Zeileis <achim.zeil...@uibk.ac.at> wrote:
>
> On Thu, 28 Jun 2018, Therneau, Terry M., Ph.D. via R-devel wrote:
>
>> I now understand the issue, which leads to a different and deeper issue
>> which is "how to assign a proper length to Surv objects".
>>
>> > Surv(c(1,2,3), c(1,0,1))
>> [1] 1 2+ 3
>>
>> The above prints as 3 elements and is conceptually 3 elements. But if I give
>> it length method to return a 3 then I need a names method, and names<- pays
>> no attention to my defined length. How do we conceive of and manage a vector
>> whose elements happen to require more than one storage slot for their
>> representation? An obvious example is the complex type, but it seems that
>> had to be baked right down into the core.
>
> I think you just have to implement all methods required to make it look like
> a vector even if it is internally a matrix. Thus, you need methods for length
> and for names and names<-. Internally, the names can be stored as row names.
I think a closer look at model.response() would help.
IIUC, the reasoning therein is that comparing
length(data[[1L]]) (aka `length(v)')
to
length(attr(data, "row.names")) (aka `nrows')
is to decide whether names are sensibly assigned to `v'. I think for Surv
objects they are not.
I suppose you could define
`names<-.Surv` <- function(...) NULL
but that seems so silly I think there must be a better way.
I am low on coffee right now, but I wonder if having a non-exported version of
model.response in the survival package would solve this without breaking
anything else.
Chuck
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