I assume that you mean you want the columns deleted. If so, this might work:
> set.seed(1)
> x <- matrix(sample(0:1,100,replace=TRUE,prob=c(.9,.1)), ncol=10)
> x
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 0 0 1 0 0 0 1 0 0 0
[2,] 0 0 0 0 0 0 0 0 0 0
[3,] 0 0 0 0 0 0 0 0 0 0
[4,] 1 0 0 0 0 0 0 0 0 0
[5,] 0 0 0 0 0 0 0 0 0 0
[6,] 0 0 0 0 0 0 0 0 0 0
[7,] 1 0 0 0 0 0 0 0 0 0
[8,] 0 1 0 0 0 0 0 0 0 0
[9,] 0 0 0 0 0 0 0 0 0 0
[10,] 0 0 0 0 0 0 0 1 0 0
> colSums(x)
[1] 2 1 1 0 0 0 1 1 0 0
> # delete columns with zero sums
> x[, which(colSums(x) != 0)]
[,1] [,2] [,3] [,4] [,5]
[1,] 0 0 1 1 0
[2,] 0 0 0 0 0
[3,] 0 0 0 0 0
[4,] 1 0 0 0 0
[5,] 0 0 0 0 0
[6,] 0 0 0 0 0
[7,] 1 0 0 0 0
[8,] 0 1 0 0 0
[9,] 0 0 0 0 0
[10,] 0 0 0 0 1
>
On 4/26/07, Milton Cezar Ribeiro <[EMAIL PROTECTED]> wrote:
> Dear all,
>
> I have some matrices which colSums are equal to zero and I would like to
> delete all them.
> How can I do that?
>
> Kind regards,
>
> miltinho
> Brazil
>
> __________________________________________________
>
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--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem you are trying to solve?
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