[R] rbind-ing numeric matrices

[Sarah Goslee]

Hi Nick,

We absolutely need a reproducible example, with code and data, to be
able to help you.

Because otherwise I can't replicate your problem:

> A <- matrix(1:5, nrow=1, ncol=5)
> B <- matrix(6:20, nrow=3, ncol=5)
> C <- rbind(A, B)
> A
     [,1] [,2] [,3] [,4] [,5]
[1,]    1    2    3    4    5
> B
     [,1] [,2] [,3] [,4] [,5]
[1,]    6    9   12   15   18
[2,]    7   10   13   16   19
[3,]    8   11   14   17   20
> C
     [,1] [,2] [,3] [,4] [,5]
[1,]    1    2    3    4    5
[2,]    6    9   12   15   18
[3,]    7   10   13   16   19
[4,]    8   11   14   17   20


Sarah

On Tue, May 1, 2012 at 11:52 AM, Nick Switanek <nswitanek at gmail.com> wrote:
> Good morning,
>
> I'm running into trouble rbind-ing numeric matrices with differing numbers
> of rows. In particular, there seem to be issues whenever a one-row numeric
> matrix is involved.
>
> Assume A is a numeric matrix with 1 row and Y columns and B is a numeric
> matrix with X rows and Y columns. Let C be the result of rbinding A and B.
> Then C is a numeric matrix with X + 1 rows and Y columns, only instead of
> the rows of B being "stacked" beneath the row of A as expected, the first Y
> elements of the 1st column of B are placed in the 2nd row of C, the
> remaining values of B are discarded, and NULL values fill out the rest of
> the matrix C.
>
> The number of columns of A and B match. The colnames of A and B match. Both
> are numeric matrices. I've pored over the rbind/cbind documentation but
> can't identify why I'm getting this behavior from rbind. I'd be extremely
> grateful for your suggestions or thoughts.
>
> Nick
>


-- 
Sarah Goslee
http://www.functionaldiversity.org