What is the difference between creating a matrix by using matrix function or as.matrix function in R?

The difference between as.matrix and matrix function is that nrow argument or ncol argument are not helpful with as.matrix function but with matrix function we can use them. Therefore, we can actual define a matrix with matrix function but if we have a data frame or data table then it can be converted to matrix by using as.matrix function.

Examples of creating matrix with as.matrix and matrix function

Example1

 Live Demo

M<−as.matrix(1:25,nrow=5)
M

Output

     [,1]
[1,]  1
[2,]  2
[3,]  3
[4,]  4
[5,]  5
[6,]  6
[7,]  7
[8,]  8
[9,]  9
[10,] 10
[11,] 11
[12,] 12
[13,] 13
[14,] 14
[15,] 15
[16,] 16
[17,] 17
[18,] 18
[19,] 19
[20,] 20
[21,] 21
[22,] 22
[23,] 23
[24,] 24
[25,] 25

Example2

 Live Demo

M<−as.matrix(1:25,ncol=5)
M

Output

    [,1]
[1,]  1
[2,]  2
[3,]  3
[4,]  4
[5,]  5
[6,]  6
[7,]  7
[8,]  8
[9,]  9
[10,] 10
[11,] 11
[12,] 12
[13,] 13
[14,] 14
[15,] 15
[16,] 16
[17,] 17
[18,] 18
[19,] 19
[20,] 20
[21,] 21
[22,] 22
[23,] 23
[24,] 24
[25,] 25

Example3

 Live Demo

M<−matrix(1:25,ncol=5)
M

Output

   [,1] [,2] [,3] [,4] [,5]
[1,] 1   6    11   16   21
[2,] 2   7    12   17   22
[3,] 3   8    13   18   23
[4,] 4   9    14    19  24
[5,] 5   10    15   20  25

Example4

 Live Demo

M<−matrix(1:25,nrow=5)
M

Output

[,1] [,2] [,3] [,4] [,5]
[1,] 1 6 11 16 21
[2,] 2 7 12 17 22
[3,] 3 8 13 18 23
[4,] 4 9 14 19 24
[5,] 5 10 15 20 25

Example5

 Live Demo

M<−matrix(1:25,nrow=5,byrow=TRUE)
M

Output

   [,1] [,2] [,3] [,4] [,5]
[1,]  1   2   3   4    5
[2,]  6   7   8   9   10
[3,] 11   12  13  14   15
[4,] 16   17  18  19   20
[5,] 21   22  23  24   25

Example6

 Live Demo

M<−matrix(1:25,nrow=5,byrow=FALSE)
M

Output

   [,1] [,2] [,3] [,4] [,5]
[1,] 1   6   11   16   21
[2,] 2   7   12   17   22
[3,] 3   8   13   18   23
[4,] 4   9   14   19   24
[5,] 5   10  15   20   25