Syntax error How to divide matrix rows by number of columns in R?

How to divide matrix rows by number of columns in R?

To divide matrix rows by number of columns in R, we can follow the below steps −

  • First of all, create a matrix.
  • Then, use apply function to divide the matrix rows by number of columns.

Create the matrix

Let’s create a matrix as shown below −

 Live Demo

M<-matrix(sample(1:100,40),ncol=2)
M

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

    [,1] [,2]
[1,]  98 93
[2,] 83 86
[3,] 65 46
[4,] 31 8
[5,] 9 58
[6,] 62 51
[7,] 96 95
[8,] 48 92
[9,] 53 56
[10,] 40 16
[11,] 54 52
[12,] 100 27
[13,] 88 29
[14,] 18 33
[15,] 57 71
[16,] 90 28
[17,] 73 77
[18,] 97 24
[19,] 84 72
[20,] 75 1

Divide the matrix rows by number of columns

Using apply function to divide the rows of M by number of columns in M −

 Live Demo

M<-matrix(sample(1:100,40),ncol=2)
M_new<-t(apply(M,1, function(x) x/length(x)))
M_new

Output

     [,1] [,2]
[1,] 49.0 46.5
[2,] 41.5 43.0
[3,] 32.5 23.0
[4,] 15.5 4.0
[5,] 4.5 29.0
[6,] 31.0 25.5
[7,] 48.0 47.5
[8,] 24.0 46.0
[9,] 26.5 28.0
[10,] 20.0 8.0
[11,] 27.0 26.0
[12,] 50.0 13.5
[13,] 44.0 14.5
[14,] 9.0 16.5
[15,] 28.5 35.5
[16,] 45.0 14.0
[17,] 36.5 38.5
[18,] 48.5 12.0
[19,] 42.0 36.0
[20,] 37.5 0.5
Updated on: 2021-08-14T07:55:23+05:30

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