I am trying to filter all the characters that are present in a that are not present in b and c. I want to do this from the list l.
a<-c("A", "B", "C", "D", "E")
b<-c("A", "E", "I", "O", "U")
c<-c("H", "E", "L", "L", "O")
l<-list(a,b,c)
So the answer should be BCD.