Is Empty
is_empty.RdReturn TRUE if a string is empty. Emptiness means that
any one of the following is true: NA, NaN,
nchar(as.character(x)) == 0L,
tolower(as.character(x)) == "na"
is_empty.RdReturn TRUE if a string is empty. Emptiness means that
any one of the following is true: NA, NaN,
nchar(as.character(x)) == 0L,
tolower(as.character(x)) == "na"