R help - Mar 2013 - Make a matrix from two lists

I am trying to write a function that makes a matrix out of two lists. As you
will see run running the function below, the result is NOT a matrix but rather a
list. Can anyone tell me what I am doing wrong?
Thanks,
John
 
test <- function(one,two) {
  cat("List One=",one,"\n")
  cat("List Two=",two,"\n")
  cat("Should be a matrix, but is
not",matrix(cbind(one,two)),"\n")
 }
x <- c(1,2,3)
y <- c(11,22,33)
test(x,y)
 
 
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology
Baltimore VA Medical Center
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Hi,

On Mar 29, 2013, at 1:29 PM, John Sorkin wrote:
> I am trying to write a function that makes a matrix out of two lists. As
you will see run running the function below, the result is NOT a matrix but
rather a list. Can anyone tell me what I am doing wrong?
> Thanks,
> John
> 
> test <- function(one,two) {
>  cat("List One=",one,"\n")
>  cat("List Two=",two,"\n")
>  cat("Should be a matrix, but is
not",matrix(cbind(one,two)),"\n")
> }
> x <- c(1,2,3)
> y <- c(11,22,33)
> test(x,y)
> 

x <- c(1,2,3)
y <- c(11,22,33)
z <- cbind(x,y)
is.matrix(z)
[1] TRUE

As you can see above, I don't get the same result.

I not sure if you want to see the matrix printed in matrix form when you have it
in test().  If that were the case then you'll want to avoid cat() and use
print() instead.
 
test <- function(one,two) {
 cat("List One=",one,"\n")
 cat("List Two=",two,"\n")
 z <- cbind(one, two)
 print(z)
}

test(x,y)
List One= 1 2 3 
List Two= 11 22 33 
     one two
[1,]   1  11
[2,]   2  22
[3,]   3  33

Cheers,
Ben


Ben Tupper
Bigelow Laboratory for Ocean Sciences
60 Bigelow Drive, P.O. Box 380
East Boothbay, Maine 04544
http://www.bigelow.org