使用R中数据帧的元素基于公式创建系数矩阵

Question

I have the following dataframe named (A) in R:

A <- data.frame("budget_range" = c("less_than_1", "1-5", "5-20", "20-50", "50-100", "100-500", "more_than_500"),
        "coefficient" = c(0.005, 0.01, 0.05, 0.2, 0.5, 1, 5))

Budget_range    Coefficient
1_less_than_1     0.005
2_1-5             0.01
3_5-20            0.05
4_20-50           0.2
5_50-100          0.5
6_100-500         1
7_more_than_500   5

I now would like to create a 7x7 matrix where each element of the matrix = min(BudgetRange1,BudgetRange2) / max(BudgetRange1,BudgetRange2).

For example with element 2,1 or 1,2 (they should be the same), the math would be 0.005/0.01 = 0.5.

It should give something like this:

   1     2     3     4     5     6     7
1  1   0.5    0.1  0.025  0.01  0.005  0.001
2  0.5  1     0.2   0.05  0.02   0.01  0.002
3  ...
4
5
6
7

Any idea how to do it? Thanks a lot in advance!

Answer 1

We can use outer to do this

outer(A$coefficient, A$coefficient, FUN = function(...) pmin(...)/pmax(...))
#    [,1]  [,2] [,3]  [,4] [,5]  [,6]  [,7]
#[1,] 1.000 0.500 0.10 0.025 0.01 0.005 0.001
#[2,] 0.500 1.000 0.20 0.050 0.02 0.010 0.002
#[3,] 0.100 0.200 1.00 0.250 0.10 0.050 0.010
#[4,] 0.025 0.050 0.25 1.000 0.40 0.200 0.040
#[5,] 0.010 0.020 0.10 0.400 1.00 0.500 0.100
#[6,] 0.005 0.010 0.05 0.200 0.50 1.000 0.200
#[7,] 0.001 0.002 0.01 0.040 0.10 0.200 1.000