removeing only rows/columns with "na" value from square ( symmetrical ) matrix.

Your problem is not well-defined. In your example below, why not
remove rows 1,2,6, and 10, all of which contain NA's? Is the matrix
supposed to be symmetric? Do NA's always occur symmetrically?

You either need to rethink what you want to do or clarify your statement of it.

-- Bert

On Sun, May 20, 2012 at 7:17 AM, Nevil Amos <nevil.amos at monash.edu> wrote:

I have some square matrices with na values in corresponding rows and
columns.

M<-matrix(1:2,10,10)
M[6,1:2]<-NA
M[10,9]<-NA
M<-as.matrix(as.dist(M))
print (M)

   1 2 3 4 5 6 7 8 9 10
1   0  2 1 2 1 NA 1 2  1  2
2   2  0 1 2 1 NA 1 2  1  2
3   1  1 0 2 1  2 1 2  1  2
4   2  2 2 0 1  2 1 2  1  2
5   1  1 1 1 0  2 1 2  1  2
6  NA NA 2 2 2  0 1 2  1  2
7   1  1 1 1 1  1 0 2  1  2
8   2  2 2 2 2  2 2 0  1  2
9   1  1 1 1 1  1 1 1  0 NA
10  2  2 2 2 2  2 2 2 NA  0


How do I remove just the row/column pair( in this trivial example row 6 and
10 and column 6 and 10) containing the NA values?

so that I end up with all rows/ columns that are not NA - e.g.

 1 2 3 4 5 7 8 9
1 0 2 1 2 1 1 2 1
2 2 0 1 2 1 1 2 1
3 1 1 0 2 1 1 2 1
4 2 2 2 0 1 1 2 1
5 1 1 1 1 0 1 2 1
7 1 1 1 1 1 0 2 1
8 2 2 2 2 2 2 0 1
9 1 1 1 1 1 1 1 0


if i use na omit I lose rows 1,2,6, and 9
which is not what I want.

thanks
--
Nevil Amos
Molecular Ecology Research Group
Australian Centre for Biodiversity
Monash University
CLAYTON VIC 3800
Australia

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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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