Epi (version 2.0)

start.Lexis: Time series methods for Lexis objects

Description

Extract the entry time, exit time, status or duration of follow-up from a Lexis object.

Usage

entry(x, time.scale = NULL, by.id=FALSE) exit(x, time.scale = NULL, by.id=FALSE)
status(x, at="exit"        , by.id=FALSE) dur(x,                    by.id=FALSE)

Arguments

x

an object of class Lexis.

time.scale

a string or integer indicating the time scale. If omitted, all times scales are used.

by.id

Logical, if TRUE, only one record per unique value of lex.id is returned; either the first, the last or for dur, the sum of lex.dur. If TRUE, the returned object have the lex.id as (row)nmes attribute.

at

string indicating the time point(s) at which status is to be measured.

Value

The entry and exit functions return a vector of entry times and exit times, respectively, on the requested time scale. If multiple time scales are requested, then a matrix is returned.The status function returns a vector giving the status at entry or exit and dur returns a vector with the lengths of the follow-up intervals.

See Also

Lexis