Hi, I've been trying to solve this error, could you help me out with it? Thank you! 
ifelse((NRIC_DF $ ALP == "S" | NRIC_DF $ ALP == "T"),
fin <- c("J", "Z", "I", "H", "G", "F", "E", "D", "C", "B", "A")[result + 1],
fin <- c("X", "W", "U", "T", "R", "Q", "P", "N", "M", "L", "K")[result + 1])
Error in c("X", "W", "U", "T", "R", "Q", "P", "N", "M", "L", "K")[result + : invalid subscript type 'list')