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

[Bert Gunter]

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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>
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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