On Sep 18, 2017, at 5:13 AM, Therneau, Terry M., Ph.D. <
therneau at mayo.edu> wrote:
This question likely has a 1 line answer, I'm just not seeing it. (2,
3, or 10 lines is fine too.)
For a vector I can do group <- match(x, unqiue(x)) to get a vector that
labels each element of x.
What is an equivalent if x is a data frame?
In the past I've use apply with past to generate "group" identifiers:
x<-data.frame("X0"=c("A","B","C","C","D","A"), "X1"=c(1,2,1,1,3,1))
apply(x, 1, paste, collapse=".")
[1] "A.1" "B.2" "C.1" "C.1" "D.3" "A.1"
The result does not have to be fast: the data set will have < 100
elements. Since this is inside the survival package, and that package is
on the 'recommended' list, I can't depend on any package outside the
recommended list.
David Winsemius
Alameda, CA, USA
'Any technology distinguishable from magic is insufficiently advanced.'
-Gehm's Corollary to Clarke's Third Law