A matrix is a two-dimensional array where each element has the same mode (numeric,character, or logical). Matrices are created with the matrix function .

Syntax:

myymatrix <- matrix(vector, nrow=number_of_rows, ncol=number_of_columns,

byrow=logical_value, dimnames=list(char_vector_rownames, char_vector_colnames

))

where

- 'vector' contains the elements for the matrix

- 'nrow' and 'ncol' specify the row and column dimensions

- 'dimnames' contains optional row and column labels stored in character vectors.

- 'byrow' indicates whether the matrix should be filled in by row (byrow=TRUE) or by column (byrow=FALSE). The default is by column.

Below we will see a 5x4 Matrix creation

> y <- matrix(1:20, nrow=5, ncol=4) q

> y

[,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

> cells <- c(1,26,24,68)

> rnames <- c("R1", "R2")

> cnames <- c("C1", "C2") w

> mymatrix <- matrix(cells, nrow=2, ncol=2, byrow=TRUE,

dimnames=list(rnames, cnames))

> mymatrix

C1 C2

R1 1 26

R2 24 68

> mymatrix <- matrix(cells, nrow=2, ncol=2, byrow=FALSE,

dimnames=list(rnames, cnames))

> mymatrix e

C1 C2

R1 1 24

R2 26 68

First, we are creating a 5x4 matrix . Then we create a 2x2 matrix with labels and fill the matrix by rows . Finally, we create a 2x2 matrix and fill the matrix by columns.