You can use the following methods to combine a list of matrices in R:

**Method 1: Combine List of Matrices by Rows**

do.call(rbind, list_of_matrices)

**Method 2: Combine List of Matrices by Columns**

do.call(cbind, list_of_matrices)

The following examples show how to use each method in practice with the following two matrices in R:

#define matrices matrix1 <- matrix(1:6, nrow=3) matrix2 <- matrix(7:12, nrow=3) #view first matrix matrix1 [,1] [,2] [1,] 1 4 [2,] 2 5 [3,] 3 6 #view second matrix matrix2 [,1] [,2] [1,] 7 10 [2,] 8 11 [3,] 9 12

**Example 1: Combine List of Matrices by Rows**

The following code shows how to use the rbind function to combine a list of matrices by rows:

#create list of matrices matrix_list <- list(matrix1, matrix2) #combine into one matrix by rows do.call(rbind, matrix_list) [,1] [,2] [1,] 1 4 [2,] 2 5 [3,] 3 6 [4,] 7 10 [5,] 8 11 [6,] 9 12

The two matrices have been combined into a single matrix by rows.

**Example 2: Combine List of Matrices by Columns**

The following code shows how to use the cbind function to combine a list of matrices by columns:

#create list of matrices matrix_list <- list(matrix1, matrix2) #combine into one matrix by columns do.call(cbind, matrix_list) [,1] [,2] [,3] [,4] [1,] 1 4 7 10 [2,] 2 5 8 11 [3,] 3 6 9 12

The two matrices have been combined into a single matrix by columns.

**Related:** An Introduction to do.call in R

**Additional Resources**

The following tutorials explain how to perform other common tasks in R:

How to Create an Empty Matrix in R

How to Convert Data Frame to Matrix in R

How to Convert List to Matrix in R