NA

R Base 3.6.2

NA is a logical constant of length 1 which contains a missing value indicator. NA can be coerced to any other vector type except raw. There are also constants NA_integer_, NA_real_, NA_complex_ and NA_character_ of the other atomic vector types which support missing values: all of these are reserved words in the R language. The generic function is.na indicates which elements are missing. The generic function is.na

Syntax

NA
is.na(x)
anyNA(x, recursive = FALSE)<p></p><p># S3 method for data.frame
is.na(x)</p><p>is.na(x) &lt;- value</p>

Arguments

Parameter	Description
`x`	an R object to be tested: the default method for is.na and anyNA handle atomic vectors, lists, pairlists, and NULL.
`recursive`	logical: should anyNA be applied recursively to lists and pairlists?
`value`	a suitable index vector for use with x.

Return Value

The default method for is.na applied to an atomic vector returns a logical vector of the same length as its argument x, containing TRUE for those elements marked NA or, for numeric or complex vectors, NaN, and FALSE otherwise. (A complex value is regarded as NA if either its real or imaginary part is NA or NaN.) dim, dimnames and names attributes are copied to the result. The default methods also work for lists and pairlists: For is.na, elementwise the result is false unless that element is a le

Details

The NA of character type is distinct from the string "NA". Programmers who need to specify an explicit missing string should use NA_character_ (rather than "NA") or set elements to NA using is.na<-. is.na and anyNA are generic: you can write methods to handle specific classes of objects, see InternalMethods. Function is.na<- may provide a safer way to set missingness. It behaves differently for factors, for example. Numerical computations using NA will normally result in NA: a possible exception is where NaN is also involved, in which case either might result (which may depend on the R platform). Logical computations treat NA as a missing TRUE/FALSE value, and so may return TRUE or FALSE if the expression does not depend on the NA operand. The default method for anyNA handles atomic vector

Examples

Example

# NOT RUN {
is.na(c(1, NA))        #> FALSE  TRUE
is.na(paste(c(1, NA))) #> FALSE FALSE

(xx <- c(0:4))
is.na(xx) <- c(2, 4)
xx                     #> 0 NA  2 NA  4
anyNA(xx) # TRUE

# Some logical operations do not return NA
c(TRUE, FALSE) & NA
c(TRUE, FALSE) | NA

# }
# NOT RUN {
## Measure speed difference in a favourable case:
## the difference depends on the platform, on most ca 3x.
x <- 1:10000; x[5000] <- NaN  # coerces x to be double
if(require("microbenchmark")) { # does not work reliably on all platforms
  print(microbenchmark(any(is.na(x)), anyNA(x)))
} else {
  nSim <- 2^13
  print(rbind(is.na = system.time(replicate(nSim, any(is.na(x)))),
              anyNA = system.time(replicate(nSim, anyNA(x)))))
}
# }
# NOT RUN {
## anyNA() can work recursively with list()s:
LL <- list(1:5, c(NA, 5:8), c("A","NA"), c("a", NA_character_))
L2 <- LL[c(1,3)]
sapply(LL, anyNA); c(anyNA(LL), anyNA(LL, TRUE))
sapply(L2, anyNA); c(anyNA(L2), anyNA(L2, TRUE))

## ... lists, and hence data frames, too:
dN <- dd <- USJudgeRatings; dN[3,6] <- NA
anyNA(dd) # FALSE
anyNA(dN) # TRUE
# }

NA

Syntax

Arguments

Return Value

Details

Examples

See Also