Hi:

Here' s one approach:

> int <- sample(1:20,10)
> m <- matrix(sample(1:40, 20), nrow = 10)
> int
 [1]  7 12  4  6  1 19 17 20 15  5
> m
      [,1] [,2]
 [1,]    9   15
 [2,]   23   32
 [3,]   40   14
 [4,]   19   38
 [5,]   28    6
 [6,]   26   18
 [7,]   34   22
 [8,]    7   35
 [9,]   21    3
[10,]   39   12
> m[m[, 1] %in% int, ]
     [,1] [,2]
[1,]   19   38
[2,]    7   35

HTH,
Dennis

On Fri, Apr 1, 2011 at 10:08 PM, Joseph N. Paulson
<josephpaulson@gmail.com>wrote:

> Hi all!
>
> I have a vector, let's say for example int <- sample(1:20,10);
> for now:
>
> now I have a matrix...
> M = m x n
> where the first column is a "feature" column and most likely shares at
> least
> one of the int (interesting) numbers.
>
> I want to extract the rows where int[] = M[,1]
>
> I thought:
> rownames(int)<-int;
> rownames(M)<-M[,1];
>
> M[rownames(int),] would work, but it doesn't... (I assume because I have
> rownames(int) that are not found in M[,1]. Neither does,
> rownames(M)==rownames(int)...
>
> Any help would be greatly appreciated!
>
> Thank you!
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

	[[alternative HTML version deleted]]

