I am getting some unexplained changes in the latest version of survival, and
finally
traced it down to this: model.response acts differently for Surv objects.
Here is a closed form example using a made up class Durv = diagnose survival.??
I tracked
it down by removing methods one by one from Surv; I had just added some new ones
so they
were my suspects.
test <- data.frame(time=1:8, status=rep(0:1, 4), age=60:67)
row.names(test) <- letters[1:8]
Durv <- function(...) {
??? temp <- cbind(...)
??? class(temp) <- "Durv"
??? temp
}
mf1 <- model.frame(Durv(time, status) ~ age, data=test)
names(model.response(mf1))
#? NULL
length.Durv <- function(x) nrow(x)
names(model.response(mf1))
#? [1] "a" "b" "c" "d" "e"
"f" "g" "h" NA? NA? NA? NA? NA? NA NA? NA
The length method for Surv objects has been around for some while, this behavior
is new.?
It caused the 'time' component of survfit objects to suddenly have names
and so was
discovered in my test suite.? I had planned to submit an update today, but now
need to
delay it.
The length of the Surv (Durv) object above is 8, BTW; the fact that it's
representation
requires either 16 elements (right censored) or 24 (interval censored) is a
footnote.
Terry Therneau
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