A categorical variable V1 in a data frame D1 can have values represented by the letters from A to Z. I want to create a subset D2, which excludes some values, say, B, N and T. Basically, I want a command which is the opposite of %in%
D2 = subset(D1, V1 %in% c("B", "N", "T"))
!(x %in% y)
). Life can be easy sometimes... – Joris Meys