-- begin included message --- > (basehazzft.ln$stra[285]) [1] stra=2 134 Levels: stra=1 stra=10 stra=100 stra=101 stra=102 ... stra=99 > c(basehazzft.ln$stra[285]) [1] 47
while the desired value is 2, I get a 47. What am I doing wrong? I tried the as.numeric function but I have the same problem.. --- end included --- The variable in question is a factor. The internal codes used for the levels of a factor variable 'x', as reported by as.numeric(x) or c(x), are not the same as the names of the levels, which appear from printing x itself. The confusing nature of factor variables makes a regular appearance on R help. I would suggest reading the section on factor variables in one of the many introductory R texts. Your question is not per se an issue with the Cox model routines. But to answer your underlying query, try substring(x, 6,10). PS If you use survfit() instead of basehaz() you will get back a survival curve object, which is often much more useful. I never use basehaz myself, but there was a cry for a function with the same name and same (limite) output as the SAS phreg option. (Basehaz calls survfit and then throws away 1/2 the information.) Terry T. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
