new behavior in model.response
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. Further useful methods for "Surv" objects might include - as.double/as.integer (presumably just extracting the "time"), - c - str Possibly also a dedicated summary. An example for such a class is our "paircomp" in "psychotools". But I'm sure there are other/better examples elsewhere. Best, Achim