[R] removing zero rows from matrix/table

[Gabor Csardi]

See ?apply

M2 <- M[ apply(M!=0, 1, any), , drop=FALSE]

Gabor

On Tue, Apr 22, 2008 at 11:52:08AM +0200, Patrick Zimmermann wrote:
> Dear R-community,
> I have matrices/tables of different sizes which may contain rows with
> only zeros. Now I would like to delete these zero lines or create new
> matrices composed only of the non-zero lines. Columns only containing
> zeros I want to preserve.
> Here an example:
> 
> [,1] [,2] [,3] [,4] [,5] [,6] [,7]
> [1,] 1 0 1 1 0 0 0
> [2,] 0 0 0 0 0 0 0
> [3,] 1 0 0 0 0 0 0
> [4,] 1 0 1 1 1 1 1
> [5,] 1 0 1 0 1 0 1
> [6,] 0 0 1 1 1 1 1
> [7,] 0 0 0 0 0 0 0
> 
> Rows 2 and 7 shall be deleted, but column 2 shall be maintained.
> I believe this should be a simple operation with basic commands, but
> have no idea how to manage it.
> Looking forward do any help,
> Patrick
> 
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-- 
Csardi Gabor <csardi at rmki.kfki.hu>    UNIL DGM