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removing columns
3 messages · nuncio m, Uwe Ligges, David Winsemius
On 03.05.2011 13:16, nuncio m wrote:
Hi list, I have a matrix with all elements of some columns are zeroes. Is it possible to remove these columns:
Xnew <- X[ , as.logical(colSums(X)), drop=FALSE] Uwe Ligges
and create a new matrix nuncio
On May 3, 2011, at 4:24 AM, Uwe Ligges wrote:
On 03.05.2011 13:16, nuncio m wrote:
Hi list, I have a matrix with all elements of some columns are zeroes. Is it possible to remove these columns:
Xnew <- X[ , as.logical(colSums(X)), drop=FALSE]
A counter-example:
X <- matrix(c(1,1,1,-1,0,1,1,1,1),3)
A fix:
> Xnew <- X[ , as.logical(colSums(abs(X))), drop=FALSE]
> Xnew
[,1] [,2] [,3]
[1,] 1 -1 1
[2,] 1 0 1
[3,] 1 1 1
Uwe Ligges
and create a new matrix nuncio
David Winsemius, MD Heritage Laboratories West Hartford, CT