A sunflowerplot crossing two categorial variables with NAs fails: ### sample: start ### set.seed(20) a <- c(letters[1:4]) z <- c(letters[23:26]) fa <- factor(sample(rep.int(a, 1000), 100, replace=T), levels=a, ordered=T) fz <- factor(sample(rep.int(z, 1000), 100, replace=T), levels=z, ordered=T) sunflowerplot(fa, fz) # okay, but: r <- xyTable(fa, fz) length(r$x)==length(r$y) length(r$x)==length(r$number) # TRUE, TRUE is.na(fa) <- sort(sample(1:100, 3)) sunflowerplot(fa, fz) # Error in rep.int(i.multi, number[number > 1]) : invalid 'times' value s <- xyTable(fa, fz) length(s$x)==length(s$y) length(s$x)==length(s$number) # TRUE, TRUE ### sample: end ### Seems to fail due to NAs, but (1) why and (2) how to get by? Thanks, *S?ren*