*! version 1.1  mh 15/4/98  arb 20/8/98
program define unique
local options "BY(string) GENerate(string) Detail"
local varlist "req ex min(1)"
local if "opt"
local in "opt"
parse "`*'"
tempvar uniq recnum count touse
local sort : sortedby
mark `touse' `if' `in'
qui gen `recnum' = _n
sort `varlist'
summ `touse', meanonly
local N = _result(18)
sort `varlist' `touse'
qui by `varlist': gen byte `uniq' = (`touse' & _n==_N)
qui summ `uniq'
di in gr "Number of unique values of `varlist' is  " in ye _result(18)
di in gr "Number of records is  "in ye "`N'"
if "`detail'" != "" {
	sort `by' `varlist' `touse'
	qui by `by' `varlist' `touse': gen int `count' = _N if _n == 1
	label var `count' "Records per `varlist'"
	if "`by'" == "" {
		summ `count' if `touse', d
	}
	else {
		by `by': summ `count' if `touse', d
	}
}
if "`by'" !="" {
	if "`generate'"=="" {
		cap drop _Unique
		local generat _Unique
	}
	else {
		confirm new var `generate'
	}

        drop `uniq'
	sort `by' `varlist' `touse'
	qui by `by' `varlist': gen byte `uniq' = (`touse' & _n==_N)
	qui by `by': replace `uniq' = sum(`uniq')
	qui by `by': gen `generate' = `uniq'[_N] if _n==1
	di in blu "variable `generate' contains number of unique values of `varlist' by `by'"
	list `by' `generate' if `generate'!=., noobs nodisplay
}
sort `sort' `recnum'
end