[R] Problems with NA's

[Thomas L Jones, PhD]

Difficulty handling NA's:
Assume that I have a numeric vector y. For simplicity, assume that it has 10 
elements. Assume that the third element has the value NA. I give it the 
following:
NA_test <- function (){
y <- numeric (10)
y [3] <- NA
if (y [3] != NA){(print ("no")}
print ("Leaving NA_test")
return ()
}# End of function

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Unfortunately, things become confused involving the NA element.
Here is the output, starting with the loading process:

----------------------------------------------------------
> NA_test <- function (){
+ y <- numeric (10)
+ y [3] <- NA
+ if (y [3] != NA){(print ("no")}
Error: syntax error in:
"y [3] <- NA
if (y [3] != NA){(print ("no")}"
> print ("Leaving NA_test")
[1] "Leaving NA_test"
> return ()
Error: no function to return from, jumping to top level
> }# End of function
Error: syntax error in "}"
>
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I have enclosed the print operation in braces to avoid possible problems 
with it.

Your advice?

Tom Jones