A generic auxiliary function that produces a numeric vector which
will sort in the same order as
an R object.
A numeric (usually integer) vector of the same length as
This is a special case of ranking, but as a less general function than
rank is more suitable to be made generic. The default
method is similar to
rank(x, ties.method = "min",
na.last = "keep"), so
NA values are given rank
NA and all
tied values are given equal integer rank.
factor method extracts the codes. The
Surv method sorts first on times and then on
status code(s), finally on
timme2 if present. Note that with
the conventional status codes this sorts individuals still alive before
The default method will unclass the object if
is.numeric(x) is true but otherwise make use of
> methods for the class of
i), and the
is.na method for the class of
x, but might be rather slow when doing so.