[R] defining columns in a matrix

[Joshua Wiley]

Dear Kindra,

I think you are talking about...

matrix(1:9, nrow=3, dimnames=list(NULL, c("First","Second","Third")))

     First Second Third
[1,]     1      4     7
[2,]     2      5     8
[3,]     3      6     9

If I am correct, what you are missing is that "dimnames" requires a
list with two elements, the rownames, and the colnames.  As Ted
pointed out an alternate is to use colnames() on the matrix after you
have created it.

I hope that helps,

Josh



On Fri, Mar 12, 2010 at 2:29 PM, Kindra Martinenko
<kmartinenko at gmail.com> wrote:
> Hi all,
> I have the following 7 x 7 matrix.  I am trying to figure out how to
> label the columns to something more descriptive other than [,1], [,2],
> etc.
> I have tried the c(x,y,z,) function, but I get a error returned
> stating that my vectors need to be the same length.  Do I need to
> convert this to something else such as a list and then repack it?
>
> Thanks,
> Kindra
>
>          Volume
> Time        [,1] [,2] [,3] [,4] [,5] [,6] [,7]
>   17:00:00 7146 4926 5394 4534 6273 6192 6189
>   17:10:00 7227 4851 5414 4620 6026 7159 5878
>   17:20:00 7477 4678 5502 4298 6516 6469 5631
>   17:30:00 6533 4608 4813 4212 6083 5837 5657
>   17:40:00 6355 4669 5106 4242 5717 5635 5282
>   17:50:00 5657 4472 4545 3860 5378 4804 5304
>   18:00:00 5338 4508 4273 4024 4666 4597 5162
>
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>



-- 
Joshua Wiley
Senior in Psychology
University of California, Riverside
http://www.joshuawiley.com/