popEpi (version 0.2.1)

splitLexisDT: Split case-level observations

Description

Split a Lexis object along one time scale (as splitLexis) with speed

Usage

splitLexisDT(lex, breaks, timeScale, merge = TRUE, drop = TRUE)

Arguments

lex

a Lexis object, splitted or not

breaks

a vector of [a,b) breaks to split data by

timeScale

a character string; name of the time scale to split by

merge

logical; if TRUE, retains all variables from the original data - i.e. original variables are repeated for all the rows by original subject

drop

logical; if TRUE, drops all resulting rows after expansion that reside outside the time window defined by the given breaks

Value

• A data.table or data.frame (depending on options("popEpi.datatable"); see ?popEpi) object expanded to accommodate split observations.

Details

splitLexisDT is in essence a data.table version of splitLexis or survSplit for splitting along a single time scale. It requires a Lexis object as input, which may have already been split along some time scale. Unlike splitLexis, splitLexisDT drops observed time outside the roof and floor of breaks by default - with drop = FALSE the functions have identical behaviour.

Examples

library(Epi)
x <- Lexis(data=sire[1000:1100],
           entry = list(fot=0, per=get.yrs(dg_date), age=dg_age),
           exit=list(per=get.yrs(ex_date)), exit.status=status)
BL <- list(fot=seq(0, 5, by = 3/12), per=c(2008, 2013))
x2 <- splitMulti(x, breaks = BL, drop = FALSE)
x3 <- splitLexisDT(x, breaks = BL$fot, timeScale = "fot", drop = FALSE)
x3 <- splitLexisDT(x3, breaks = BL$per, timeScale = "per", drop = FALSE)
x4 <- splitLexis(x,  breaks = BL$fot, time.scale = "fot")
x4 <- splitLexis(x4, breaks = BL$per, time.scale = "per")
## all produce identical results