Hello, I need to print a screen message after a test. >list<-c("10","1","100","10") >ifelse(all(list %in% c(1,10,100)==TRUE),cat("YES\n"),cat("NO\n")) YES Error in ifelse(all(l %in% c(1, 10, 100) == TRUE), cat("YES\n"), cat("NO\n")) : replacement has length zero I have the correct answer, YES, but with an Error. Why? TY for any help Arnaud Gaboury A2CT2 Ltd.