title: How can I solve UserDefaults set error in my variable from myModel?
body: <p>I want to set my variable with using UserDefault and I tried many times but it return error every time.</p>
  
  <p>What have I missed?</p>
  
  <p>Model </p>
  
  <pre><code>import Foundation
  
  struct MyModel: Codable{
      var one: String?
      var two: String?
  }
  </code></pre>
  
  <p>Variable</p>
  
  <pre><code>var savedData: [String : MyModel] {
          get {
              return UserDefaults.standard.object(forKey: "key") as! [String : MyModel]? ?? [String : MyModel]()
          }
          set (newData) {
              UserDefaults.standard.set(newData, forKey: "key")
          }
      }
  </code></pre>
  
  <p>Code</p>
  
  <pre><code> self.savedData[position!] = self.myModel
  </code></pre>
  
  <p>I cant understand this error. What do I have to understand about this error?</p>
  
  <pre><code>0   CoreFoundation                      0x00000001022951bb __exceptionPreprocess + 331
      1   libobjc.A.dylib                     0x0000000101240735 objc_exception_throw + 48
      2   CoreFoundation                      0x0000000102295015 +[NSException raise:format:] + 197
      3   CoreFoundation                      0x00000001021acdb8 _CFPrefsValidateValueForKey + 312
      4   CoreFoundation                      0x00000001021ad24c -[CFPrefsSource setValues:forKeys:count:copyValues:removeValuesForKeys:count:from:] + 380
      5   CoreFoundation                      0x00000001021ad5dc -[CFPrefsSource setValues:forKeys:count:copyValues:from:] + 28
      6   CoreFoundation                      0x00000001021ad633 -[CFPrefsSource setValue:forKey:from:] + 67
      7   CoreFoundation                      0x000000010228ba9e __108-[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:]_block_invoke + 318
      8   CoreFoundation                      0x000000010228b1ea normalizeQuintuplet + 314
      9   CoreFoundation                      0x000000010228b954 -[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:] + 100
      10  CoreFoundation                      0x0000000102267b4b -[_CFXPreferences setValue:forKey:appIdentifier:container:configurationURL:] + 91
      11  CoreFoundation                      0x000000010226bfa5 _CFPreferencesSetAppValueWithContainer + 117
      12  Foundation                          0x0000000100ce3ce1 -[NSUserDefaults(NSUserDefaults) setObject:forKey:] + 55
      13  X                                   0x00000001006e6937 $S13X21ViewViewControllerC9savedDataSDySSAA12MyModelVGvs + 391
      14  X                                   0x00000001006e6982 $S13X21ViewViewControllerC9savedDataSDySSAA12MyModelVGvmytfU_ + 18
      15  X                                   0x00000001006f1b69 $S13X21ViewViewControllerC11getDateData4dateyAA10DateModelV_tFy10Foundation0H0VSg_So13NSURLResponseCSgs5Error_pSgtcfU_ + 2361
      16  X                                   0x00000001006f4e26 $S13X21ViewViewControllerC11getDateData4dateyAA10DateModelV_tFy10Foundation0H0VSg_So13NSURLResponseCSgs5Error_pSgtcfU_TA + 54
      17  X                                   0x00000001006d2dd0 $S10Foundation4DataVSgSo13NSURLResponseCSgs5Error_pSgIegggg_So6NSDataCSgAGSo7NSErrorCSgIeyByyy_TR + 336
      18  CFNetwork                           0x0000000103f15940 __75-[__NSURLSessionLocal taskForClass:request:uploadFile:bodyData:completion:]_block_invoke + 19
      19  CFNetwork                           0x0000000103f2bb0c __49-[__NSCFLocalSessionTask _task_onqueue_didFinish]_block_invoke + 172
      20  Foundation                          0x0000000100cadf9e __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 7
      21  Foundation                          0x0000000100cadea5 -[NSBlockOperation main] + 68
      22  Foundation                          0x0000000100caac14 -[__NSOperationInternal _start:] + 689
      23  Foundation                          0x0000000100cb0c4b __NSOQSchedule_f + 227
      24  libdispatch.dylib                   0x0000000104e52595 _dispatch_call_block_and_release + 12
      25  libdispatch.dylib                   0x0000000104e53602 _dispatch_client_callout + 8
      26  libdispatch.dylib                   0x0000000104e5654d _dispatch_continuation_pop + 565
      27  libdispatch.dylib                   0x0000000104e55927 _dispatch_async_redirect_invoke + 859
      28  libdispatch.dylib                   0x0000000104e6400a _dispatch_root_queue_drain + 351
      29  libdispatch.dylib                   0x0000000104e649af _dispatch_worker_thread2 + 130
      30  libsystem_pthread.dylib             0x00000001052436dd _pthread_wqthread + 619
      31  libsystem_pthread.dylib             0x0000000105243405 start_wqthread + 13
  </code></pre>