Epi (version 2.56)

cbind.Lexis: Combining a Lexis objects with data frames or other Lexis objects

Description

A Lexis object may be combined side-by-side with data frames. Or several Lexis objects may stacked, possibly increasing the number of states and time scales.

Usage

# S3 method for Lexis
cbind(...)
# S3 method for Lexis
rbind(...)

Value

A Lexis object. rbind renders a Lexis

object with timescales equal to the union of timescales in the arguments supplied. Values of a given timescale are set to NA

for rows corresponding to supplied objects. cbind basically just adds columns to an existing Lexis object.

Arguments

...

For cbind a sequence of data frames or vectors of which exactly one has class Lexis. For rbind a sequence of Lexis objects, supposedly representing follow-up in the same population.

Author

Bendix Carstensen, http://bendixcarstensen.com

Details

Arguments to rbind.Lexis must all be Lexis objects; except for possible NULL objects. The timescales in the resulting object will be the union of all timescales present in all arguments. Values of timescales not present in a contributing Lexis object will be set to NA. The breaks for a given time scale will be NULL if the breaks of the same time scale from two contributing Lexis objects are different.

The arguments to cbind.Lexis must consist of at most one Lexis object, so the method is intended for amending a Lexis object with extra columns without losing the Lexis-specific attributes.

See Also

subset.Lexis

Examples

# A small bogus cohort
xcoh <- structure( list( id = c("A", "B", "C"),
                      birth = c("14/07/1952", "01/04/1954", "10/06/1987"),
                      entry = c("04/08/1965", "08/09/1972", "23/12/1991"),
                       exit = c("27/06/1997", "23/05/1995", "24/07/1998"),
                       fail = c(1, 0, 1) ),
                     .Names = c("id", "birth", "entry", "exit", "fail"),
                  row.names = c("1", "2", "3"),
                      class = "data.frame" )

# Convert the character dates into numerical variables (fractional years)
xcoh <- cal.yr( xcoh, format="%d/%m/%Y", wh=2:4 )
# See how it looks
xcoh
str( xcoh )

# Define as Lexis object with timescales calendar time and age
Lcoh <- Lexis( entry = list( per=entry ),
                exit = list( per=exit, age=exit-birth ),
         exit.status = fail,
                data = xcoh )
Lcoh
cbind( Lcoh, zz=3:5 )

# Lexis object wit time since entry time scale
Dcoh <- Lexis( entry = list( per=entry, tfe=0 ),
                exit = list( per=exit ),
         exit.status = fail,
                data = xcoh )
# A bit meningless to combie these two, really...
rbind( Dcoh, Lcoh )

# Split different places
sL <- splitLexis( Lcoh, time.scale="age", breaks=0:20*5 )
sD <- splitLexis( Dcoh, time.scale="tfe", breaks=0:50*2 )
sDL <- rbind( sD, sL )