Check of Length 0 or Missing

DESCRIPTION:

Check to see whether the input is either NA or a vector of length 0.

USAGE:

is.missing(x) 

REQUIRED ARGUMENTS:

x
input to check.

VALUE:

T if the input is a vector of length 0; is.na(x) otherwise.

EXAMPLES:

is.missing(numeric(0)) 
is.missing(NA) 
is.missing(c(1,2,3,NA,5))