[R] sum(is.na(c(...)) -> negative number; bug or feature?

[Barnet Wagman]

As I understand it, sum() treats a logical vectors as 1's and 0's, so
that

> is.logical(c(FALSE,TRUE,FALSE))
[1] TRUE
> sum(c(FALSE,TRUE,FALSE))
[1] 1

However,  summing the results of an is.na() yields a
negative number.  Eg

> is.na(c(1,NA,3))
[1] FALSE  TRUE FALSE
> is.logical(is.na(c(1,NA,3)))
[1] TRUE
> sum(is.na(c(1,NA,3)))
[1] -1

(This is from R Version 0.64.0, under Redhat Linux 5.2 (compiled from
scratch
 using egcs-g77-1.0.3a-14, although I can't imagine that's relevant).

Is this a bug, or is there something about sum() that I'm missing?

Thanks

--------------------
Barnet Wagman

wagman at enteract.com
773-645-8369

1361 N. Hoyne
Chicago, IL 60622
---------------------



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