[R] question about cbind()

Gabor Grothendieck ggrothendieck at gmail.com
Sun Aug 20 02:05:49 CEST 2006


First 4 colums of builtin data frame anscombe as a matrix:

  as.matrix(anscombe[1:4])


On 8/19/06, jz7 at duke.edu <jz7 at duke.edu> wrote:
> Dear all,
>
> I have a question about how to get a matrix by combining a large number of
> columns from a data file. Suppose I read a file which have 1000 columns
> by:
>
> test = read.table("dat.txt", header=F)
>
> I know I could use "cbind()". It's easy to do when the number of columns
> is small (i.e. cbind(test$V1, test$V2)). But how about build a matrix "X"
> by combine the first 500 columns. Is there an easy way to write the
> expression?
>
> Thanks so much!
>
> Jeny
>
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