Ordering a varlist in Stata code - sorting

Question

I see the following as a programming exercise, rather than a statistically grounded way of doing things.
Basically, I'd like to run N logistic regressions with one predictor variable and then for each variable store the variable name with its chi-squared value. After all predictions are done, I want to display each predictor variable ordered by chi-squared from highest to lowest.
So far I have the following:
local depvar binvar1
local indepvars predvar1 predvar2 predvar3
* expand and check collinearity *
_rmdcoll `depvar' `indepvars', expand
local indepvars "`r(varlist)'"
* first order individual variables by best chi-squared *
local vars
local chis
foreach v in `indepvars' {
di "RUN: logistic `depvar' `v'"
quietly logistic `depvar' `v'
* check if variable is not omitted (constant and iv) *
if `e(rank)' < 2 {
di "OMITTED (rank < 2): `v'"
continue
}
* check if chi-squared is > 0 *
if `e(chi2)' <= 0 {
di "OMITTED (chi2 <= 0): `v'"
continue
}
* store *
local vars "`vars' `v'"
local chis "`chis' `e(chi2)'"
di "ADDED: `v' (chi2: `e(chi2)')"
}
* ... now sort each variable (from varlist vars) by chi2 (from varlist chis) ... *
How would I sort each variable by the returned chi-square in the last line and then display the list of variables with their chi-squared ordered from highest chi-squared to lowest chi-squared?
To be clear, if the following varlists resulted from the above:
local vars predvar1 predvar2 predvar3
local chis 2 3 1
Then I would like to get something like the following:
local ordered predvar2 3 predvar1 2 predvar3 1
Or, alternatively,
local varso predvar2 predvar1 predvar3
local chiso 3 2 1

Answer 1

Here is one way to do it.
local depvar binvar1
local indepvars predvar1 predvar2 predvar3
* expand and check collinearity *
_rmdcoll `depvar' `indepvars', expand
local indepvars "`r(varlist)'"
* first order individual variables by best chi-squared *
gen chisq = .
gen vars = ""
local i = 1
foreach v in `indepvars' {
di "RUN: logistic `depvar' `v'"
quietly logistic `depvar' `v'
* check if variable is not omitted (constant and iv) *
if `e(rank)' < 2 {
di "OMITTED (rank < 2): `v'"
}
* check if chi-squared is > 0 *
else if `e(chi2)' <= 0 {
di "OMITTED (chi2 <= 0): `v'"
}
* store *
else {
quietly replace vars = "`v'" in `i'
quietly replace chisq = -e(chi2) in `i'
local ++i
di "ADDED: `v' (chi2: `e(chi2)')"
}
}
sort chisq
replace chisq = -chisq
l vars chisq if chisq < ., noobs