> a <- 1:9 > b <- c(4,5) > setdiff(a, b) # [1] 1 2 3 6 7 8 9 > union(a, b) # [1] 1 2 3 4 5 6 7 8 9 > intersect(a, b) # [1] 4 5 > setequal(a, b) # [1] FALSE