Concatenating Matrices in R

Question

How can I concatenate matrices of same columns but different number of rows? For example, I want to concatenate a ( dim(a) = 15 7000 ) and b (dim(b) = 16

Answer 1

Sounds like you're looking for rbind:

> a<-matrix(nrow=10,ncol=5)
> b<-matrix(nrow=20,ncol=5)
> dim(rbind(a,b))
[1] 30  5

Similarly, cbind stacks the matrices horizontally.

I am not entirely sure what you mean by the last question ("Can I do this for matrices of different rows and columns.?")