stata 程序写法 静态运行写法 help return

 program mysum, rclass
                syntax varname
                return local varname `varlist'
                tempvar new
                quietly {
                        count if !missing(`varlist')
                        return scalar N = r(N)
                        gen double `new' = sum(`varlist')
                        return scalar sum = `new'[_N]
                        return scalar mean = return(sum)/return(N)
                }
        end

. clear

. webuse auto,clear
(1978 automobile data)

. mysum mpg

. ret list

scalars:
               r(mean) =  21.2972972972973
                r(sum) =  1576
                  r(N) =  74

macros:
            r(varname) : "mpg"

.