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\name{Surv-methods}
\alias{Math.Surv}
\alias{Ops.Surv}
\alias{Summary.Surv}
\alias{anyDuplicated.Surv}
\alias{as.character.Surv}
\alias{as.data.frame.Surv}
\alias{as.matrix.Surv}
\alias{c.Surv}
\alias{duplicated.Surv}
\alias{format.Surv}
\alias{head.Surv}
\alias{is.na.Surv}
\alias{length.Surv}
\alias{mean.Surv}
\alias{median.Surv}
\alias{names.Surv}
\alias{names<-.Surv}
\alias{quantile.Surv}
\alias{plot.Surv}
\alias{rep.Surv}
\alias{rep.int.Surv}
\alias{rep_len.Surv}
\alias{rev.Surv}
\alias{t.Surv}
\alias{tail.Surv}
\alias{unique.Surv}
\title{Methods for Surv objects}
\description{The list of methods that apply to \code{Surv} objects}
\usage{
\method{anyDuplicated}{Surv}(x, ...)
\method{as.character}{Surv}(x, ...)
\method{as.data.frame}{Surv}(x, ...)
\method{as.matrix}{Surv}(x, ...)
\method{c}{Surv}(...)
\method{duplicated}{Surv}(x, ...)
\method{format}{Surv}(x, ...)
\method{head}{Surv}(x, ...)
\method{is.na}{Surv}(x)
\method{length}{Surv}(x)
\method{mean}{Surv}(x, ...)
\method{median}{Surv}(x, na.rm=FALSE, ...)
\method{names}{Surv}(x)
\method{names}{Surv}(x) <- value
\method{quantile}{Surv}(x, probs, na.rm=FALSE, ...)
\method{plot}{Surv}(x, ...)
\method{rep}{Surv}(x, ...)
\method{rep.int}{Surv}(x, ...)
\method{rep_len}{Surv}(x, ...)
\method{rev}{Surv}(x)
\method{t}{Surv}(x)
\method{tail}{Surv}(x, ...)
\method{unique}{Surv}(x, ...)
}
\arguments{
\item{x}{a \code{Surv} object}
\item{probs}{a vector of probabilities}
\item{na.rm}{remove missing values from the calculation}
\item{value}{a character vector of up to the same length as \code{x}, or
\code{NULL}}
\item{\ldots}{other arguments to the method}
}
\details{
These functions extend the standard methods to \code{Surv} objects.
(There is no central index of R methods, so there may well be useful
candidates that the author has missed.)
The arguments and results from these are mostly as expected, with the
following further details:
\itemize{
\item The \code{as.character} function uses "5+" for right censored
at time 5, "5-" for left censored at time 5, "[2,7]" for an
observation that was interval censored between 2 and 7,
"(1,6]" for a counting process data denoting an observation which
was at risk from time 1 to 6, with an event at time 6, and
"(1,6+]" for an observation over the same interval but not ending
with and event.
For a multi-state survival object the type of event is appended to
the event time using ":type".
\item The \code{print} and \code{format} methods make use of
\code{as.character}.
\item The \code{length} of a \code{Surv} object is the number of
survival times it contains, not the number of items required to
encode it, e.g., \code{x <- Surv(1:4, 5:8, c(1,0,1,0)); length(x)}
has a value of 4.
Likewise \code{names(x)} will be NULL or a vector of length 4.
(For technical reasons, any names are actually stored in the
\code{rownames} attribute of the object.)
\item For a multi-state survival object \code{levels} returns the
names of the endpoints, otherwise it is NULL.
\item The \code{median}, \code{quantile} and \code{plot} methods
first construct a survival curve using \code{survfit}, then apply
the appropriate method to that curve.
\item The \code{xtfrm} method, which underlies sort and order,
sorts by time, with censored after uncensored within a tied time.
For an interval censored observation the midpoint is used.
For (time1, time2) counting process data, sorting is by time2, censoring,
and then time1.
\item The \code{unique} method treats censored and uncensored
observations at the same time as distinct, it returns a Surv object.
\item The concatonation method \code{c()} is asymmetric, its first
argument determines the execution path. For instance
\code{c(Surv(1:4), Surv(5:6))} will return a Surv object of length 6,
\code{c(Surv(1:4), 5:6)} will give an error, and
\code{c(5:6, Surv(1:4))} is equivalent to
\code{c(5:6, as.vector(Surv(1:4)))} which is a numeric of length 10.
}
}
\seealso{ \code{\link{Surv}}}
\keyword{survival}
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