[R] using nrow to identify one row

[Gabor Csardi]

Try 

temp[1,,drop=FALSE]

See ?"[" for the explanation.

Gabor

On Fri, Mar 14, 2008 at 04:46:10PM -0400, Gregory Gentlemen wrote:
> Hi fellow R-users,
> 
> I have run into a problem when trying to identify the number of rows in a matrix. Say we have an arbitrary 5 by 5 matrix called temp:
> 
> temp <- matrix(norm(25), nrow=5)
> 
> The problem is that nrow(temp[1,]) returns NULL. I would like it to return 1 because in my larger program I am indexing the rows of large matrices according to another variable and I need to test when the resulting matrices have 0, 1 or more rows.
> 
> Thanks in advance for any assistance.
> 
> Best regards,
> Gregory Gentlemen
> 
> 
> 
>        
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-- 
Csardi Gabor <csardi at rmki.kfki.hu>    UNIL DGM