[R] help with element-by-element sum with NA
R. Michael Weylandt
michael.weylandt at gmail.com
Tue Jul 24 06:48:19 CEST 2012
Perhaps something like:
Reduce(function(x,y){x[is.na(x)] <- 0; y[is.na(y)] <- 0; x + y}, list(A,B,C))
Not the most elegant, but it will get the job done.
Michael
On Mon, Jul 23, 2012 at 3:47 PM, Thiago Couto <couto.thiagoba at gmail.com> wrote:
> Hi,
>
> I have three matrices which could be, for example:
> A = 0, NA
> NA, 3
>
> B = 1, NA
> 0, NA
>
> C = 1, NA
> 1, 1
>
> (The point is that they all may have NA's in some cells)
>
> QUESTION: How do I perform a element-by-element sum of the elements of
> these three matrices (A + B + C), ignoring NA's, to obtain:
>
> D = 2, NA
> 1, 4
>
> In reality I am handling much larger matrices (not just 2x2).
>
> Thank you for any help!
>
> [[alternative HTML version deleted]]
>
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