To construct the matrix that would result from your cbind() command, do this:
x <- 1:15
matrix( rep(x,5) , ncol=5)
[,1] [,2] [,3] [,4] [,5]
[1,] 1 1 1 1 1
[2,] 2 2 2 2 2
[3,] 3 3 3 3 3
[4,] 4 4 4 4 4
[5,] 5 5 5 5 5
[6,] 6 6 6 6 6
[7,] 7 7 7 7 7
[8,] 8 8 8 8 8
[9,] 9 9 9 9 9
[10,] 10 10 10 10 10
[11,] 11 11 11 11 11
[12,] 12 12 12 12 12
[13,] 13 13 13 13 13
[14,] 14 14 14 14 14
[15,] 15 15 15 15 15
This doesn't, of course, use cbind() at all. It uses a different and
simpler method to directly construct the matrix. You can easily
generalize it to more columns by using a variable instead of 5 in the
rep() command, and for the ncol arg to matrix().
-Don
At 12:27 PM -0800 2/10/10, Xu Wang wrote:
Hi,
I would like to be able to repeat a string within a command. I think there
is an easy way but I can not figure out how.
Here is an example.
x<-1:15
I would like to turn this into the following matrix:
xm<-cbind(x,x,x,x,x)
But I would like to do so by having a command that repeats x within the
cbind command. Does that make sense? I have tried various things mainly
involving the commands "rep" and "paste" but cannot get it.
cbind(rep('x',times=5))
I am guessing that this is not good programming etiquette? Something seems
off about it. But still, I would like to know how to do it.
I do understand that I can use a for loop to easily accomplish the desired
output but am looking for a solution similar to the above syntax.
Thank you for any ideas,
Xu Wang
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--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
925-423-1062
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