search for: type_pch

...= '21' " ) plot(df$Y,df$X,pch= df$pch_type) This plots subjects for type 1 and 2 with symbols A and B (this is what expected) however subjects with type = 3 are plotted with a charcater 2 instead of a pch=21. I understand that this is due to the fact that the created vector "type_pch" cannot be a mixture between characters and numerics ... I tried to use a list for that purpsoe but fail... Any suggestions would be grateful, Many thanks, Bernard --------------------------------- [[alternative HTML version deleted]]