[R] help with element-by-element sum with NA
arun
smartpink111 at yahoo.com
Tue Jul 24 06:24:56 CEST 2012
HI,
Try this:
A<-matrix(c(0,NA,NA,3),ncol=2)
B<-matrix(c(1,0,NA,NA),ncol=2)
C<-matrix(c(1,1,NA,1),ncol=2)
AB<-ifelse(is.na(A),ifelse(is.na(B),NA,B), ifelse(is.na(B), A, A+B))
ABC<-ifelse(is.na(AB),ifelse(is.na(C),NA,C),ifelse(is.na(C),AB,AB+C))
ABC
[,1] [,2]
[1,] 2 NA
[2,] 1 4
A.K.
----- Original Message -----
From: Thiago Couto <couto.thiagoba at gmail.com>
To: r-help at r-project.org
Cc:
Sent: Monday, July 23, 2012 4:47 PM
Subject: [R] help with element-by-element sum with NA
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!
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