How to add a new row to an R matrix

Question

I want to add a new row to an existing matrix. Which R function should I use?

Answer 1

You can use the rbind() function to add a new row to an existing R matrix. The number of columns in the new row should match the number of columns in the existing matrix, i.e., if the existing matrix has k columns, the new row should also have k columns.

Here is an example:

mm <- matrix(c(1:20), ncol = 4, nrow = 5)
mm <- rbind(mm, c(21:24))

The old value of the matrix 'mm':

> mm
     [,1] [,2] [,3] [,4]
[1,]    1    6   11   16
[2,]    2    7   12   17
[3,]    3    8   13   18
[4,]    4    9   14   19
[5,]    5   10   15   20

The new value of the matrix 'mm':

> mm
     [,1] [,2] [,3] [,4]
[1,]    1    6   11   16
[2,]    2    7   12   17
[3,]    3    8   13   18
[4,]    4    9   14   19
[5,]    5   10   15   20
[6,]   21   22   23   24