| is.na {base} | R Documentation |
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
NAinteger, NAreal, NAcomplex and NAcharacter 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<- sets elements To NA.
is.na(x);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 length-one atomic vector And the single element of that vector Is regarded as NA Or NaN (note that any Is.na method for the class of the element Is ignored). anyNA(recursive = FALSE) works the same way as Is.na; anyNA(recursive = TRUE) applies anyNA (with method dispatch) to each element.
The data frame method For Is.na returns a logical matrix With the same dimensions As the data frame, And With dimnames taken from the row And column names Of the data frame.
anyNA(NULL) Is false; Is.na(NULL) Is logical(0) (no longer warning since R version 3.5.0).