| 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.
The generic function is.na returns a logical vector
of the same “form” as its argument x, containing TRUE
for those elements marked NA or NaN (!)
and FALSE otherwise.
dim, dimnames and names attributes are preserved.
The generic function is.na<- sets elements to NA.
NA
is.na(x)
is.na.data.frame(x)
is.na(x) <- value
x |
an R object to be tested. |
value |
a suitable index vector for use with |
For character vectors the value "NA" represents missingness.
is.na(x) works elementwise when x is a list.
The method dispatching is C-internal, rather than via
UseMethod.
Function is.na<- may provide a safer way to set missingness.
It behaves differently for factors, for example.
NaN, is.nan, etc.
and the utility function complete.cases.
na.action, na.omit, na.fail
on how methods can be tuned to deal with missing values.
is.na(c(1,NA)) #> F TRUE
is.na(paste(c(1,NA)))#> F FALSE