An example of this is found in the coxph function in the survival library. Look at it for
guideance.
Within a coxph formula the expression "tt(x)" means to use a time transform on variable x.
The tt function is a fake, defined as tt <- function(x) x, whose only purpose is to
allow the user to
On 29/01/2014 9:20 AM, Therneau, Terry M., Ph.D. wrote:
An example of this is found in the coxph function in the survival library.
Look at it for
guideance.
Within a coxph formula the expression "tt(x)" means to use a time transform on
variable x.
The tt function is a fake, defined as tt <-
For the special tt mark in a formula, the answer is "mine". Other than that coxph handles
formulas in a completely standard way.
I don't see any other solution, frankly, unless I want to get really complex. If formulas
were not handled in an odd way, I'd simply add tt() to my namespace, not e
