clear
sysuse auto
generate price1 =price
generate price2 =price

ds, has(type numeric)
local varlist1 "`r(varlist)'"
local varlist1 : subinstr local varlist1 "price" ""
*display "`varlist1'"
local varlist2 "`varlist1'"

foreach var of local varlist1 {
// varlist1 cannot be altered inside this loop
	*display "`varlist2'"
	capture assert `var' == price
	if (_rc==0 & "`var'" ~= "price") {
		display "`var'"
 		local varlist2 : subinstr local varlist2 "`var'" ""
		display "`varlist2'"
		drop `var'
		}
	}