
I assume that you are working in package MatrixCalc. Let’s
say you have a matrix X. You can call the columns of X this way:

X[,1] for the first column

X[,2] for the second column

X[,3] for the third column

Etc.

So let’s say that you want to add the first and third column,
then you would just do X[,1] + X[,3]

If you wanted to call that quantity later on, it might be helpful
to give it a name:

NewQ <- X[,1] + X[,3]
Good luck,Rita
On Wed, Jun 22, 2011 at 2:35 AM, Nabila Binte Zahur <nab...@nus.edu.sg> wrote:
> Dear Sirs/Madam,
>
> I am a beginner to R, and I am currently working on a data matrix which looks 
> like this:
>
>> head(oligo)
>
>        ko:K00001 ko:K00003 ko:K00005 ko:K00008 ko:K00009 ko:K00010 ko:K00012
> AAA       370          631                  365               67           
> 164             455       491
> KAA       603         1208                 170              157        68     
>            495       922
> NAA        60         110                     10                7            
> 44               51        94
> DAA       183         802                    41               62          26  
>             166       263
> CAA        58            12                    58                1            
>    1              23         8
> TAA       451          468                  201                90       131   
>            320       518
>
>
> For certain specific columns, I need to merge the columns in such a way that 
> the elements get added together.
>
> For example, in order to merge the first and the second columns, my output 
> for the first row shld be
>
>           ko:K00001/ko:K00003
> AAA       1001 (i.e. 370+631)
> KAA        1811 (i.e. 603+1208)
>
>
> and so on for the whole column.
>


Rita ===================================== "If you think education is expensive, try ignorance."--Derek Bok
 		 	   		  
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