Sorry. There was a mistake in my previous code. Please disregard it
and use the following:
> r1=c(1,2,3,7,1,3,2)
> r2=c(4,5,7,8,1,4,3)
> test=matrix(c(r1,r2),nrow=2,ncol=7,byrow=TRUE)
> colnames(test)<-c("a1","a2","b1","b2","b3","c1","c2")
> test
[,1] [,2] [,3] [,4] [,5] [,6] [,7]
[1,] 1 2 3 7 1 3 2
[2,] 4 5 7 8 1 4 3
> grep("a",(colnames(test)))
[1] 1 2
> test.a<-test[,grep("a",(colnames(test)))]
> test.a
a1 a2
[1,] 1 2
[2,] 4 5
Kyle H. Ambert
Graduate Student, Dept. Behavioral Neuroscience
Oregon Health & Science University
[EMAIL PROTECTED]
On Jul 31, 2007, at 10:35 AM, yuvika wrote:
> Hello all,
>
> I have a matrix whose column names look like
>
> a1 a2 b1 b2 b3 c1 c2
> 1 2 3 7 1 3 2
> 4 6 7 8 1 4 3
>
> Now, I can have any number of a's. not just two as shown above
> and same goes for b's and c's. I need to extract all the a's
> columns and put them in another matrix, extract all b's columns and
> put them in some matrix and same goes for "c". How can I identify
> such pattern and get subsets of this matrix depending on columns
> names?
>
> I will appreciate a quick reply.
> Thanks a lot.
>
>
> ---------------------------------
>
>
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>
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