[Rd] numerics from a factor
therneau at mayo.edu
Fri Mar 15 18:47:01 CET 2013
A problem has been pointed out by a French user of the survival package and I'm looking
for a pointer.
> options(OutDec= ",")
> fit <- survfit(Surv(1:6 /2) ~ 1)
 NA 1 NA 2 NA 3
A year or two ago some test cases that broke survfit were presented to me. The heart of
the problem was numbers that were almost identical, where table(x) and unique(x) gave
different counts of distinct values.
The solution was to use "ftime <- factor(time)" at the top of the code, and do all the
calulations using the integer levels of the factor as the unique time points. At the very
end the numeric component "time" of the result is created using
as.numeric(levels(ftime)). It's this last line that breaks.
I could set the OutDec option within survfit and reset when I leave using on.exit. Any
other simple solutions? Any other ways I could get caught by this issue?
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