Concatenating Matrices in R

r matrix concatenation
Concerned_Citizen picture Concerned_Citizen · Sep 6, 2011 · Viewed 111.9k times · Source

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 7000) and I want the result to be a matrix of 31 rows by 7000 columns. Can I do this for matrices of different rows and columns.? Say I want to combine a matrix of 15 rows and 7000 columns with another of 16 rows and 7500 columns. Can I create one dataset with that?

Answer

NPE picture NPE · Sep 6, 2011

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.?")

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