| NA {base} | R Documentation |
NA is a logical constant of length 1 which contains
a missing value indicator. NA can be freely coerced to any
other vector type.
as.na ignores its argument and returns the value NA.
is.na takes a vector argument and returns a logical vector
of the same length containing TRUE for those elements marked
NA and FALSE otherwise. dim, dimnames and
names attributes are preserved.
NA
is.na(x)
as.na(x)
complete.cases.