swift - Array of structs: How to save in coredata? -

i´m trying save array of structs coredata. did lot of research, cannot find solution. here´s i´ve got:

import cocoa import coredata  class viewcontroller: nsviewcontroller {      struct studentsstruct {         let firstname: string         let lastname: string         let age: int     }       let studentsdata: [studentsstruct] = [studentsstruct(firstname: "albert", lastname: "miller", age: 24), studentsstruct(firstname: "susan", lastname: "gordon", age: 24), studentsstruct(firstname: "henry", lastname: "colbert", age: 24)]       override func viewdidload() {         super.viewdidload()          let student: student = nsentitydescription.insertnewobject(forentityname: "student", into: databasecontroller.getcontext()) as! student           items in studentsdata {             student.firstname = studentsstruct.firstname             student.lastname = studentsstruct.lastname             student.age = studentsstruct.age         }          databasecontroller.savecontext()         let fetchrequest: nsfetchrequest<student> = student.fetchrequest()          print (student)     } } 

the databasecontroller solution i´ve got tutorial: https://www.youtube.com/watch?v=da6w7wdh0dw it´s not important, it´s making "getcontext" function. whats important, in teh commandline "student.firstname = studentsstruct.firstname" i´m getting error "instance member "firstname" cannot used on type viewcontroller.studentstruct. after trying , trying, i´m running out of ideas how array of structs coredata.

this databasecontroller file:

import foundation import  coredata   class databasecontroller  {      private init() {     }     class func getcontext() -> nsmanagedobjectcontext {         return databasecontroller.persistentcontainer.viewcontext     }      // mark: - core data stack      static var persistentcontainer: nspersistentcontainer = {                 let container = nspersistentcontainer(name: "studentcorefile")         container.loadpersistentstores(completionhandler: { (storedescription, error) in             if let error = error {                                fatalerror("unresolved error \(error)")             }         })         return container     }()      class func savecontext () {         let context = databasecontroller.persistentcontainer.viewcontext         if context.haschanges {             {                 try context.save()             } catch {                 // replace implementation code handle error appropriately.                 // fatalerror() causes application generate crash log , terminate. should not use function in shipping application, although may useful during development.                 let nserror = error nserror                 fatalerror("unresolved error \(nserror), \(nserror.userinfo)")             }         }     }  } 

for in advance!

ok, right, forgot execute fetchrequest. here´s current code:

import cocoa import coredata  class viewcontroller: nsviewcontroller {      struct studentsstruct {         let firstname: string         let lastname: string         let age: int     }       let studentsdata: [studentsstruct] = [studentsstruct(firstname: "albert", lastname: "miller", age: 24), studentsstruct(firstname: "susan", lastname: "gordon", age: 24), studentsstruct(firstname: "henry", lastname: "colbert", age: 24)]       override func viewdidload() {         super.viewdidload()          let student: student = nsentitydescription.insertnewobject(forentityname: "student", into: databasecontroller.getcontext()) as! student           item in studentsdata {             let student: student = nsentitydescription.insertnewobject(forentityname: "student", into: databasecontroller.getcontext()) as! student             student.firstname = item.firstname             student.lastname = item.lastname             student.age = int16(item.age)         }         databasecontroller.savecontext()         let fetchrequest: nsfetchrequest<student> = student.fetchrequest()          {             let searchresults = try databasecontroller.getcontext().fetch(fetchrequest)             print("number of results: \(searchresults.count)")             result in searchresults [student] {                 print(student)             }          } catch {              print ("error")          }      } } 

it´s running without errors. i´m getting 32 search results. every entry is: age = 0; firstname = nil; lastname = nil;

for comparison, code, without loop working:

import cocoa import coredata  class viewcontroller: nsviewcontroller {      override func viewdidload() {         super.viewdidload()          let student: student = nsentitydescription.insertnewobject(forentityname: "student", into: databasecontroller.getcontext()) as! student          student.firstname = "henry"         student.lastname = "miller"         student.age = 22          databasecontroller.savecontext()         let fetchrequest: nsfetchrequest<student> = student.fetchrequest()          {             let searchresults = try databasecontroller.getcontext().fetch(fetchrequest)             print("number of results: \(searchresults.count)")             result in searchresults [student] {                 print(student)             }         } catch {              print ("error")         }      }  } 

you need access item in loop accessing same object student object in loop instead of need create new student in every iteration of loop.

for item in studentsdata {     //create new student in loop     let student = nsentitydescription.insertnewobject(forentityname: "student", into: databasecontroller.getcontext()) as! student     //to firstname, lastname , age access item     student.firstname = item.firstname     student.lastname = item.lastname     student.age = item.age } //save context databasecontroller.savecontext()