How to multiply corresponding row values in a matrix with single row matrix in R?

To multiply row values in a matrix having multiple rows with single row matrix in R, we can follow the below steps −

• First of all, create a matrix with multiple rows and a matrix with single row.

• Then, use mapply function to multiply row values in those matrices.

Example

Create the first matrix

Let’s create a matrix as shown below −

M1<-matrix(rpois(100,10),ncol=4) M1

Output

On executing, the above script generates the below output(this output will vary on your system due to randomization) −

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

Create the second matrix

Let’s create a matrix as shown below −

M2<-matrix(c(1,0,2,5),nrow=1) M2

Output

On executing, the above script generates the below output(this output will vary on your system due to randomization) −

 [,1] [,2] [,3] [,4] [1,] 1 0 2 5

Multiply values from two matrices

Using mapply function to multiply row values in the matrix M1 having multiple rows with single row matrix M2 −

M1<-matrix(rpois(100,10),ncol=4) M2<-matrix(c(1,0,2,5),nrow=1) mapply(`*`,M1,M2)

Output

 [1] 11 0 36 55 9 0 14 35 10 0 24 40 14 0 10 55 11 0 26 40 8 0 20 45 12 [26] 0 22 60 9 0 18 75 10 0 16 70 9 0 16 50 11 0 30 80 16 0 4 70 11 0 [51] 22 60 10 0 8 35 10 0 28 40 8 0 18 75 8 0 26 40 9 0 24 20 14 0 10 [76] 30 6 0 24 75 8 0 18 60 12 0 20 60 5 0 24 40 16 0 24 35 16 0 24 45