在处理工业企业数据库时，遇到这样的问题，代码如下：
forvalues i = 1998/2007{
        disp "File `i'"
        use `"D:\360Downloads\stata15\`i'.dta"',clear
    gen id_in_source = _n
                                keep id_in_source a_dep admin_expense bdat uniqueid id name legal_person town prov ///
             c_dep cost current_asset e_collective phone zip product1 bdat industry_code dq revenue ///
                 e_foreign e_HMT e_individual e_legal_person e_state export employment profit///
                 fa_net fa_original fa_total fin_expense input interest inventory ls neighborhood///
                 new_producet output owners_equity paidup_captital prefecture product2 product3///
                 sales_expense scale street subsidy tax tax_add total_asset total_debt type///
                 va village wage
       
                saveold m`i'.dta,replace
}