cap pro drop sortuniq1
pro define sortuniq1

          /*this program generates a list of  
            unique values of v in ascending order */

args v

sort `v'
tempvar vv
gen `vv'=.
qui replace `vv'=`v'[1] in 1

local i=2
local j=1

while `i' <=_N{
   if `vv'[`j'] < `v'[`i']{
       local j=`j'+1
       qui replace `vv'=`v'[`i'] in `j'
   }
local i=`i'+1
}

qui replace `v'=`vv'
list `v'
end