Save names and scalar from a community-contributed command in a matrix

[Felix Kaysers]

Some community-contributed commands like xtoverid do not return a matrix of results similar to xtreg but sets of scalars, but I want to return them in a matrix with their names for easier referencing in a matrix after I have run a command and give the matrix a simple name. I know how to extract the scalars manually from this post OR how to automatically extract the names of the scalar from this post.

use https://www.stata-press.com/data/r18/union.dta, clear
xtset idcode year
xtreg union age black
xtoverid

* Matrix with the results
matrix A = r(j) \r(jdf) \ r(jp)

* Extract the scalar names
local haus: r(scalars)

Desired result would be a matrix like this, where the name of the matrix would be "hausmantest":
stat
j -294.19553
jp 55.691719
jdf -5.2825724

[Felix Kaysers]

I figured that I need to write a little command myself. I have started to write the program but it does not work as intended. It returns nothing

capture program drop mtxextract
program define mtxextract
    args name
    local scalarnames: r(scalars)
    local scalarcount: word count `scalars''
    matrix define m`name'
    matrix rownumber = `scalarcount'
    matrix rownames = `scalarnames'
    matrix colnames = stat
    foreach na of `scalarnames' {
        local i = 0
        matrix[i,1] = r(`na')
        i++
    }
end

[Felix Kaysers]

Here is a working version of a little program to extract the scalars from a command and put them into a matrix. Particularly useful when one wants to report the values directly in putdocx.

program define mtxextract
args name
local scalarnames: r(scalars)
local scalarcount: word count `scalarnames'

* Create a matrix to store the scalar values
matrix `name' = J(`scalarcount', 1, .)
matrix rownames `name' = `scalarnames'
matrix colnames `name' = "stat"

* Initialize the index
local i = 1

* Iterate over scalar names and assign their values to the matrix
foreach na of local scalarnames {
matrix `name'[`i', 1] = r(`na')
local ++i
}
matrix list `name'
end