R: Time series and other methods for Lexis objects

entry.Lexis {Epi} | R Documentation

## Time series and other methods for Lexis objects

### Description

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

### 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 )
     transient( x )
     absorbing( x )
     preceding( x, states )
        before( x, states )
    succeeding( x, states )
         after( x, states )

### 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)names attribute.
`at` | string indicating the time point(s) at which status is to be measured. Possible values are "exit" or "entry".
`states` | Character vector of states.

### 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, a matrix is returned.

The `status` function returns a vector giving the status at "`at`" (either '`entry`' or '`exit`') and `dur` returns a vector with the lengths of the follow-up intervals.

`entry`, `exit`, `status` and `dur` return vectors of length `nrow(x)` if `by.id=FALSE`; if `by.id=TRUE` a vector of length `length(unique(lex.id))`.

The functions `transient` and `absorbing` return character vectors of the transient, resp. absorbing states in `x`. These are necessariy disjoint but the union may be a proper subset of `levels(x)`, since the latter may have levels that are never assumed by either `lex.Cst` or `lex.Xst`.

`preceding` returns a character vector with names of the states of the Lexis object `x` from which one of the states in `states` can be reached directly - the preceding states. `before` is just a synonym for `preceding`.

`succeeding` returns a character vector with names of the states of the Lexis object `x` that can be reached directly from one of the states in `states`. `after` is just a synonym for `succeeding`.

### Author(s)

Martyn Plummer & Bendix Carstensen

### See Also

`Lexis`

[Package Epi version 2.37 Index]