[R] Discarding a matrix based on the rowSums value

[Sarah Goslee]

Hi,

You write below:
> What I specifically need is a way to write "If any of the elements of the
> SUMROW vector == N.1s then flag <-true else flag<-false".

And in fact, ?any is just what you need, as you said.

any(SUMROW == N.1s)

should do the trick.

Sarah

On Mon, Nov 21, 2011 at 10:58 AM, Juan Antonio Balbuena <balbuena at uv.es> wrote:
> Hello
> I would appreciate your help on the followig. I want to generate random
> binary matrices but I need to discard those with all-1 rows. That is, for a
> 10x10 matrix with five 1's
>
>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
>  [1,]    0    0    0    0    0    0    0    0    0     1
>  [2,]    0    0    0    0    0    0    1    0    0     0
>  [3,]    0    0    0    0    0    0    1    0    0     0
>  [4,]    0    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,]    0    0    0    0    0    0    0    0    0     0
>  [8,]    0    0    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    1    1    0    0     0
>
> would be passed on to further computations, whereas
>
>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
>  [1,]    0    0    0    0    0    0    0    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,]    0    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,]    0    0    0    0    0    0    0    0    0     0
>  [8,]    0    0    0    0    0    0    0    0    0     0
>  [9,]    0    0    0    0    0    0    0    0    0     0
> [10,]    0    1    0    1    0    1    1    0    0     1
> must be discarded.
>
> For any N.1s <= Nrow, I am trying
>
> Nrow = 10
> Ncol = 10
> N.1s = 5
> flag <- TRUE
> while (flag == TRUE) {
> m <- matrix ((sample (c(rep(1, each=N.1s), rep(0,
> each=((Ncol*Nrow)-N.1s))))), Nrow)
> SUMROW <- rowSums(m)
>        if (SUMROW == N.1s) {flag <- TRUE} else {flag <- FALSE}
>        }
> }
>
> but I get this warning
> Warning message:
> In if (SUMROW == N.1s) { :
>  the condition has length > 1 and only the first element will be used
>
> What I specifically need is a way to write "If any of the elements of the
> SUMROW vector == N.1s then flag <-true else flag<-false".
>
> Any help would be much appreciated.
>



-- 
Sarah Goslee
http://www.functionaldiversity.org