Dear list,
I would like to expand a DF with all the missing levels of a variable.
a <- c(2,2,3,4,5,6,7,8,9)
a.cut <- cut(a, breaks=c(0,2,6,9,12), right=FALSE )
(x <- data.frame(a, a.cut))
# In 'x' the level "[0,2)" is "missing".
AddMissingLevel <- function(xdf) {
xfac <- factor( c("[0,2)", "[2,6)", "[6,9)", "[9,12)") )
xlevels <- levels(xfac)
if(length(xlevels) != nlevels(factor(xdf$a.cut))) {
v <- setdiff(xlevels, factor(xdf$a.cut))
u <- data.frame(a = 0, a.cut = v)
x <- rbind(u, x)
}
return(x)
}
AddMissingLevel(x)
Does a more general approach exist, e.g. using "expand.grid"?
Thanks for any help!!
Patrick
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
