Identify missing values in a sequence / perform asymmetric difference between two lists

Question

Using R, I want to efficiently identify which values in a sequence are missing. I've written the below example of how I do it. There must be a better way. Can someone help?

data.list=c(1,2,4,5,7,8,9)

full.list=seq(from = 1, to = 10, by =1)

output <- c()
for(i in 1:length(full.list)){
    holder1 <- as.numeric(any(data.list == i))
    output[i] <- holder1
}

which(output == 0)

Answer 1

Another possible solution

 setdiff(full.list,data.list)

Answer 2

full.list[!full.list %in% data.list]