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rmatrixconcatenation

Concatenating Matrices in R

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 also do this for matrices with a different number of 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?

Solution

  • 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.?")