# How to replicate a matrix by rows in R?

The replication of matrix by rows means that repeating a matrix one or more times but row-wise. For example, if we have a matrix that contains only one row and three columns then the replication of that matrix three times will repeat that one row three times. This can be done by using rep function along with matrix function as shown in the below example.

## Example

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

Replicating matrix M twice −

## Example

matrix(rep(t(M),2),ncol=ncol(M),byrow=TRUE)

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

Replicating matrix M thrice −

## Example

matrix(rep(t(M),3),ncol=ncol(M),byrow=TRUE)

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

Replicating matrix M five times −

## Example

matrix(rep(t(M),5),ncol=ncol(M),byrow=TRUE)

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

Replicating matrix M five times −

## Example

matrix(rep(t(M),6),ncol=ncol(M),byrow=TRUE)

## 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
[6,] 1 6 11 16 21
[7,] 2 7 12 17 22
[8,] 3 8 13 18 23
[9,] 4 9 14 19 24
[10,] 5 10 15 20 25
[11,] 1 6 11 16 21
[12,] 2 7 12 17 22
[13,] 3 8 13 18 23
[14,] 4 9 14 19 24
[15,] 5 10 15 20 25
[16,] 1 6 11 16 21
[17,] 2 7 12 17 22
[18,] 3 8 13 18 23
[19,] 4 9 14 19 24
[20,] 5 10 15 20 25
[21,] 1 6 11 16 21
[22,] 2 7 12 17 22
[23,] 3 8 13 18 23
[24,] 4 9 14 19 24
[25,] 5 10 15 20 25
[26,] 1 6 11 16 21
[27,] 2 7 12 17 22
[28,] 3 8 13 18 23
[29,] 4 9 14 19 24
[30,] 5 10 15 20 25