I want to change the following dataset to long format. The data example is given below: There are three variables: pbratio, pr and mcap. Date is in the first row. The long format should follow the order:

stock_id stock date pr pbratio mcap

Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input str54 stock str10(pbratio pr mcap)
""                                        "01-03-2000" "01-08-2000" "02-08-2000"
"20 Microns Ltd."                         ""           ""           ""          
"3I Infotech Ltd."                        ""           ""           ""          
"3M India Ltd."                           "10.96"      "714.25"     "677.35"    
"3P Land Holdings Ltd."                   "0.12"       ""           ""          
"52 Weeks Entertainment Ltd."             ""           ""           ""          
"5Paisa Capital Ltd."                     ""           ""           ""          
"63 Moons Technologies Ltd."              "28.89"      "104.25"     "120.9"     
"7Nr Retail Ltd."                         ""           ""           ""          
"7Seas Entertainment Ltd."                ""           ""           ""          
"A & M Febcon Ltd."                       ""           ""           ""          
"A 2 Z Infra Engg. Ltd."                  ""           ""           ""          
"A A Plus Tradelink Ltd."                 ""           ""           ""          
"A A R Commercial Co. Ltd. [Merged]"      ""           ""           ""          
"A A R V Infratel Ltd."                   ""           ""           ""          
"A B B India Ltd."                        "2.46"       "40.73"      "40.59"     
"A B C Gas (International) Ltd."          "4.32"       "2"          "2"         
"A B C India Ltd."                        "0.11"       ""           ""          
"A B M Knowledgeware Ltd."                "2.09"       "4.13"       "4.25"      
"A C C Ltd."                              "2.12"       "113.05"     "116.7"     
"A C E Edutrend Ltd."                     ""           ""           ""          
"A C I Infocom Ltd."                      "2.33"       ""           ""          
"A D C India Communications Ltd."         "7.24"       "456.95"     "441.1"     
"A D F Foods Ltd."                        "0.28"       "7.05"       "7.7"       
"A D S Diagnostic Ltd."                   ""           ""           ""          
"A F Enterprises Ltd."                    ""           ""           ""          
"A G I Greenpac Ltd."                     "0.89"       "25.8"       ""          
"A G I Infra Ltd."                        ""           ""           ""          
"A G S Transact Technologies Ltd."        ""           ""           ""          
"A I A Engineering Ltd."                  ""           ""           ""          
"A I Champdany Inds. Ltd."                ""           ""           ""          
"A Infrastructure Ltd."                   ""           ""           ""          
"A J R Infra & Tolling Ltd."              ""           ""           ""          
"A K Capital Services Ltd."               ""           ""           ""          
"A K I India Ltd."                        ""           ""           ""          
"A K M Lace & Embrotex Ltd."              ""           ""           ""          
"A K Spintex Ltd."                        ""           ""           ""          
"A M D Industries Ltd."                   ""           ""           ""          
"A M I Organics Ltd."                     ""           ""           ""          
"A M J Land Holdings Ltd."                "0.2"        "5.2"        "5.29"      
"A M S Polymers Ltd."                     ""           ""           ""          
"A N G Lifesciences India Ltd."           ""           ""           ""          
"A N S Inds. Ltd."                        ""           ""           ""          
"A P L Apollo Tubes Ltd."                 ""           ""           ""          
"A P M Industries Ltd."                   "0.16"       ""           "2.2"       
"A P T Packaging Ltd."                    ""           ""           ""          
"A R C Finance Ltd."                      ""           ""           ""          
"A R S S Infrastructure Projects Ltd."    ""           ""           ""          
"A S I Industries Ltd."                   "0.43"       ""           ""          
"A S M Technologies Ltd."                 "5.11"       "6.7"        "6.47"      
"A T N International Ltd."                ""           "21.1"       "21.15"     
"A T V Projects India Ltd."               ""           "1.15"       "1.25"      
"A U Small Finance Bank Ltd."             ""           ""           ""          
"A V I Polymers Ltd."                     ""           ""           ""          
"A V I Products India Ltd."               "0.91"       ""           ""          
"A V T Natural Products Ltd."             "0.66"       "1.88"       ""          
"A Y M Syntex Ltd."                       "1.66"       ""           ""          
"A-1 Acid Ltd."                           ""           ""           ""          
"Aadhaar Ventures India Ltd."             "2.93"       "8.5"        ""          
"Aadi Industries Ltd."                    ""           ""           "1.25"      
"Aagam Capital Ltd."                      "2.07"       ""           ""          
"Aananda Lakshmi Spg. Mills Ltd."         ""           ""           ""          
"Aanchal Ispat Ltd."                      ""           ""           ""          
"Aar Shyam (India) Invst. Co. Ltd."       ""           ""           ""          
"Aaradhana Realties Ltd."                 ""           ""           ""          
"Aarcon Facilities Ltd."                  ""           ""           ""          
"Aarey Drugs & Pharmaceuticals Ltd."      ""           ""           ""          
"Aarnav Fashions Ltd."                    ""           ""           ""          
"Aartech Solonics Ltd."                   ""           ""           ""          
"Aarti Drugs Ltd."                        "0.83"       ""           ""          
"Aarti Industries Ltd."                   "0.62"       ""           ""          
"Aarti Surfactants Ltd."                  ""           ""           ""          
"Aarvee Denims & Exports Ltd."            "0.13"       ""           ""          
"Aashka Hospitals Ltd."                   ""           ""           ""          
"Aastamangalam Finance Ltd."              "0.81"       ""           ""          
"Aaswa Trading & Exports Ltd."            ""           ""           ""          
"Aavas Financiers Ltd."                   ""           ""           ""          
"Aayush Food & Herbs Ltd."                ""           ""           ""          
"Aban Offshore Ltd."                      ""           "3.77"       "3.78"      
"Abans Enterprises Ltd."                  ""           ""           ""          
"Abate A S Inds. Ltd."                    "0.92"       "4.9"        ""          
"Abbott India Ltd."                       "4.87"       "337.2"      "319.6"     
"Abhayam Trading Ltd."                    ""           "16.2"       "17.25"     
"Abhijit Trading Co. Ltd."                ""           ""           ""          
"Abhinav Capital Services Ltd."           ""           ""           ""          
"Abhinav Leasing & Finance Ltd."          ""           ""           ""          
"Abhishek Corporation Ltd."               ""           ""           ""          
"Abhishek Finlease Ltd."                  ""           ""           ""          
"Abhishek Infraventures Ltd."             ""           ""           ""          
"Abirami Financial Services (India) Ltd." ""           ""           ""          
"Accedere Ltd."                           ""           "10"         "9.95"      
"Accel Ltd."                              "1.81"       "14"         "13.15"     
"Accelya Solutions India Ltd."            "5.59"       "116.8"      "118"       
"Ace Engitech Ltd."                       ""           ""           ""          
"Ace Men Engg. Works Ltd."                ""           ""           ""          
"Ace Software Exports Ltd."               "2.6"        "21.3"       "21.4"      
"Acewin Agriteck Ltd."                    ""           ""           ""          
"Achal Investments Ltd."                  ""           ""           ""          
"Achyut Healthcare Ltd."                  ""           ""           ""          
"Acil Cotton Inds. Ltd."                  "1.28"       ""           ""          
end