title: save custom array into Core Data
body: <p>i have this code to save an simple string array into core data und convert it back to an array:</p>
  
  <pre><code>// Convert it to binary data
  let array = ["Haus", "Tier","Tür"]
  let x = NSKeyedArchiver.archivedData(withRootObject: positionen)
  
  // Convert it to an array
  let data = coreData.value(forKey: "arrayPos") as! NSData
  let unarchiveObject = NSKeyedUnarchiver.unarchiveObject(with: data as Data)
  let arrayObject = unarchiveObject as! [String]
  </code></pre>
  
  <p>But if would like save an array like this:</p>
  
  <pre><code>struct ArrayData {
      var positionsname:String
      var anzahl:Double
      var einheit:String
      var einzelpreis:Double
      var typ:String
      var katalog:Bool
  }
  var array = [ArrayData ]()
  </code></pre>
  
  <p>My app will crashes.</p>
  
  <pre><code>2017-06-15 09:38:48.212788+0200 Programm[9364:608571] -[_SwiftValue encodeWithCoder:]: unrecognized selector sent to instance 0x6080000f4700
  2017-06-15 09:38:48.214663+0200 Programm[9364:608571] [General] -[_SwiftValue encodeWithCoder:]: unrecognized selector sent to instance 0x6080000f4700
  2017-06-15 09:38:48.285393+0200 Programm[9364:608571] [General] (
      0   CoreFoundation                      0x00007fffb49ac57b __exceptionPreprocess + 171
      1   libobjc.A.dylib                     0x00007fffc9bf01da objc_exception_throw + 48
      2   CoreFoundation                      0x00007fffb4a2cf14 -[NSObject(NSObject) doesNotRecognizeSelector:] + 132
      3   CoreFoundation                      0x00007fffb491fc93 ___forwarding___ + 1059
      4   CoreFoundation                      0x00007fffb491f7e8 _CF_forwarding_prep_0 + 120
      5   Foundation                          0x00007fffb63ac95a _encodeObject + 1241
      6   Foundation                          0x00007fffb63adf0c -[NSKeyedArchiver _encodeArrayOfObjects:forKey:] + 460
      7   Foundation                          0x00007fffb63ac95a _encodeObject + 1241
      8   Foundation                          0x00007fffb63e8492 +[NSKeyedArchiver archivedDataWithRootObject:] + 156
      9   Programm                            0x000000010002177b _TFC8Programm18DokumentController12saveCoreDatafT_T_ + 907
      10  Programm                            0x0000000100020ef9 _TFC8Programm18DokumentController11getObjectIDfCSo14NSNotificationT_ + 377
      11  Programm                            0x00000001000213da _TToFC8Programm18DokumentController11getObjectIDfCSo14NSNotificationT_ + 58
      12  CoreFoundation                      0x00007fffb493954c __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 12
      13  CoreFoundation                      0x00007fffb493944b _CFXRegistrationPost + 427
      14  CoreFoundation                      0x00007fffb49391b2 ___CFXNotificationPost_block_invoke + 50
      15  CoreFoundation                      0x00007fffb48f7782 -[_CFXNotificationRegistrar find:object:observer:enumerator:] + 2018
      16  CoreFoundation                      0x00007fffb48f676b _CFXNotificationPost + 667
      17  Foundation                          0x00007fffb6338907 -[NSNotificationCenter postNotificationName:object:userInfo:] + 66
      18  Programm                            0x0000000100003eae _TFC8Programm16KundenController20showSelectedDocumentfT_T_ + 2094
      19  Programm                            0x0000000100003458 _TFC8Programm16KundenController21outlineViewClickedRowfCSo13NSOutlineViewT_ + 5672
      20  Programm                            0x000000010000366a _TToFC8Programm16KundenController21outlineViewClickedRowfCSo13NSOutlineViewT_ + 58
      21  libsystem_trace.dylib               0x00007fffca7033a7 _os_activity_initiate_impl + 53
      22  AppKit                              0x00007fffb2b9a721 -[NSApplication(NSResponder) sendAction:to:from:] + 456
      23  AppKit                              0x00007fffb267ecc4 -[NSControl sendAction:to:] + 86
      24  AppKit                              0x00007fffb26f5d10 -[NSTableView _sendAction:to:row:column:] + 111
      25  AppKit                              0x00007fffb26f450f -[NSTableView mouseDown:] + 7439
      26  AppKit                              0x00007fffb26f25d0 -[NSOutlineView mouseDown:] + 74
      27  AppKit                              0x00007fffb2d1624f -[NSWindow(NSEventRouting) _handleMouseDownEvent:isDelayedEvent:] + 6341
      28  AppKit                              0x00007fffb2d12a6c -[NSWindow(NSEventRouting) _reallySendEvent:isDelayedEvent:] + 1942
      29  AppKit                              0x00007fffb2d11f0a -[NSWindow(NSEventRouting) sendEvent:] + 541
      30  AppKit                              0x00007fffb2b96681 -[NSApplication(NSEvent) sendEvent:] + 1145
      31  AppKit                              0x00007fffb2411427 -[NSApplication run] + 1002
      32  AppKit                              0x00007fffb23dbe0e NSApplicationMain + 1237
      33  Programm                            0x000000010001319d main + 13
      34  libdyld.dylib                       0x00007fffca4d1235 start + 1
      35  ???                                 0x0000000000000003 0x0 + 3
  )
  2017-06-15 09:38:48.286692+0200 Programm[9364:608571] *** -[NSKeyedArchiver dealloc]: warning: NSKeyedArchiver deallocated without having had -finishEncoding called on it.
  </code></pre>
  
  <p>can anyone explain me, what i do wrong?
  i working with swift 3 for OS X</p>