For example, accordging to expDomain1 to expDomain4, I want to generate var6, which includes the distinct values of expDomain 1 to expDomain 4.
Thanks so much!
Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input str32 expDomain1 str103 expDomain2 str32 expDomain3 str39 expDomain4 str58 var6
""                           ""                           ""                                 ""  ""                                                          
"1.电子信息"             "1.电子信息"             "1.电子信息"                   "0" "1.电子信息0"                                           
"1.电子信息"             "1.电子信息"             "1.电子信息"                   "0" "1.电子信息0"                                           
"1.电子信息"             "1.电子信息"             "1.电子信息"                   "0" "1.电子信息0"                                           
"6.新能源与高效节能" "6.新能源与高效节能" "6.新能源与高效节能"       "0" "6.新能源与高效节能0"                               
""                           ""                           ""                                 ""  ""                                                          
"1.电子信息"             "1.电子信息"             "5.资源环境与可持续发展" "0" "1.电子信息5.资源环境与可持续发展0"           
"1.电子信息"             "1.电子信息"             "1.电子信息"                   "0" "1.电子信息0"                                           
"1.电子信息"             "3.新材料"                "5.资源环境与可持续发展" "0" "1.电子信息3.新材料5.资源环境与可持续发展0"
"1.电子信息"             "1.电子信息"             "1.电子信息"                   "0" "6.新能源与高效节能0"                               
end