Array multiplication with different dimensions in R-CodePudding

I have an array and want to make a probability table for each matrix of dimensions 1 and 2. For example, consider this:

A <- array(1:12,c(2,2,3))
print(A)
, , 1

     [,1] [,2]
[1,]    1    3
[2,]    2    4

, , 2

     [,1] [,2]
[1,]    5    7
[2,]    6    8

, , 3

     [,1] [,2]
[1,]    9   11
[2,]   10   12

I want each of the 2x2 matrices become probability tables with sum 1 for each, i.e. each 2x2 matrix is divided by its sum of element. For this, I ran the below code by first taking sum and then creating an array with the same dimension.

Asum <- apply(A,3,sum)

B <- array(rep(Asum,each=length(A[,,1])),dim(A))

A/B
, , 1

     [,1] [,2]
[1,]  0.1  0.3
[2,]  0.2  0.4

, , 2

          [,1]      [,2]
[1,] 0.1923077 0.2692308
[2,] 0.2307692 0.3076923

, , 3

          [,1]      [,2]
[1,] 0.2142857 0.2619048
[2,] 0.2380952 0.2857143

Is there a better way to do this?

CodePudding user response：

You can use proportions():

proportions(A, margin = 3)

, , 1

     [,1] [,2]
[1,]  0.1  0.3
[2,]  0.2  0.4

, , 2

          [,1]      [,2]
[1,] 0.1923077 0.2692308
[2,] 0.2307692 0.3076923

, , 3

          [,1]      [,2]
[1,] 0.2142857 0.2619048
[2,] 0.2380952 0.2857143