Hi,

I would like to add a variable to a global variable list only if they are not already included. I have a set of independent variables that I need to add one by one to a global "current" varlist. The code below adds the variable regardless if already included in the "current" variable list. I want to add the variable only if it is not already included. If already included, skip and add next one. Anyone knows how to modify the code below? Thanks.

Code:
* This is the CURRENT list of variables
global M3 "LogSize MOM12 DY MOM36   retvol Debt_Price Sales_Price  mom1 rd_mve turn    bm agr chatoia egr grCAPX grltnoa invest  ROE  CEI hire   ChLTI ill  TAN indmom idiovol nincr LogIssues36 ES divo Accruals_old chmom_old  sgr pchsale_pchrect"

* Defining new models to test. Starting from model M5, M6...
local t 5
* Add one by one variables. I would like to incorporate a condition that skip the variable in this list if already included in the CURRENT list (M3) above:
local plus "  ROA  LogAG MOM6   Accruals_old Accruals  LogIssues12 Beta StdDev Turnover  cash chmom chnanalyst         chcsho chinv  grltnoa invest pchsale_pchinvt  GP_A OP_BE  NOA  chmom_old grltnoa_old divi divo   pchgm_pchsale pchsale_pchrect pctacc sgr ms OSc  ChCOL ChNNCWC ChNNCOA ChNCOA  ChNCOL ChLTI NWCCh AL    stdev_turn_w turn_w"
foreach add in `plus' {
    global M`t' $M3 `add'
    di `t'
    di "${M`t'}"
    di "`add'"
    local t = (`t' + 1)
}