R: Remove transitions from a Lexis object.

rm.tr {Epi} | R Documentation

## Remove transitions from a Lexis object.

### Description

Sometimes certain transitions are not of interest. This function removes these and assigns the risk time in the target state of the transitions to the originating state.

### Usage

    rm.tr(obj, from, to)

### Arguments

`obj` | A `Lexis` object.
`from` | Character; name of the state from which the transition to be purged originates. Must be a valid state name for `obj`.
`to` | Character; name of the state to which the transition to be purged targets. Must be a valid state name for `obj`.

### Details

The function removes all transitions from `from` to `to`, and assigns all risk time in the `to` state after the transition (`lex.dur`) to the `from` state. This is only done for risk time in `to` occurring directly after `from`. Risk time in `to` occurring after a transition from states different from `from` is not affected. Transitions from `to` to another state, `other`, say, will be changed to transitions from `from` to `other`.

### Value

A `Lexis` object with the indicated transition removed.

### Author(s)

Bendix Carstensen, http://bendixcarstensen.com.

### See Also

`Relevel`

### Examples

    data(DMlate)
    dml <- Lexis( entry = list(Per=dodm, Age=dodm-dobth, DMdur=0 ),
                   exit = list(Per=dox),
            exit.status = factor(!is.na(dodth),labels=c("DM","Dead")),
                   data = DMlate )

    # A small subset for illustration
    dml <- subset( dml, lex.id %in% c(13,15,20,28,40) )

    # Cut the follow-up at start of insulin therapy
    dmi <- cutLexis( dml, cut = dml$doins,
                          pre = "DM",
                    new.state = "Ins" )[,1:10]

    # How does it look?
    dmi

    # Remove all transitions DM -> Ins
    rm.tr( dmi, "DM", "Ins" )

[Package Epi version 2.44 Index]