On 4/4/2006 3:38 PM, [EMAIL PROTECTED] wrote:
> Full_Name: c fillekes
> Version: Version 2.2.1 (2005-12-20 r36812)
> OS: Gentoo Linux kernel 2.6.12
> Submission from: (NULL) (129.116.71.233)
>
>
>
>
> "Not Available" is of course not a numeric:
> R
>
>> is.numeric (NA)
> [1] FALSE
>
> But for some reason, all arithmetic operations on NA's are
> in fact numeric, even if it's with other NA's.
>
>
>> is.numeric (NA+NA)
> [1] TRUE
>> is.numeric (NA^2)
> [1] TRUE
>> is.numeric (NA-NA)
> [1] TRUE
>> is.numeric (NA*NA)
> [1] TRUE
>> is.numeric (NA/NA)
> [1] TRUE
>>
>
> This is not the expected thing.
But it is the documented thing, so it is not a bug:
"'is.numeric' returns 'TRUE' if its argument is of mode '"numeric"'
(type '"double"' or type '"integer"') and not a factor, and
'FALSE' otherwise."
The value is irrelevant. You probably want to use "is.numeric(x) &&
all(is.finite(x))" to get the result you're expecting.
Duncan Murdoch
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