base (version 3.3.1)

xtfrm: Auxiliary Function for Sorting and Ranking

Description

A generic auxiliary function that produces a numeric vector which will sort in the same order as x.

Usage

xtfrm(x)

Arguments

x

an R object.

Value

A numeric (usually integer) vector of the same length as x.

Details

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.

The 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 deaths.

The default method will unclass the object if is.numeric(x) is true but otherwise make use of == and > methods for the class of x[i] (for integers i), and the is.na method for the class of x, but might be rather slow when doing so.

This is an internal generic primitive, so S3 or S4 methods can be written for it.

See Also

rank, sort, order.