问题:

I'm trying to put the results of a fetch request into an array. My code:

let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate     let managedContext = appDelegate.managedObjectContext     let fetchRequest = NSFetchRequest(entityName: "CLIENTS")     var mobClients = [NSManagedObject]()     var arrayAllPhoneNumbers = [String]()      do {         let results = try managedContext.executeFetchRequest(fetchRequest)         mobClients = results as! [NSManagedObject]          for clientPhoneNumber in mobClients {              let myClientPhoneNumber = clientPhoneNumber.valueForKey("clientsMobilePhoneNumber") as! String             print(myClientPhoneNumber)             //The numbers print out just fine, one below the other             //             //Now the results need to go into the array I've declared above ---> arrayAllPhoneNumbers              messageVC.recipients = arrayAllPhoneNumbers // Optionally add some tel numbers          }      } catch         let error as NSError {             print("Could not fetch \(error), \(error.userInfo)")     }

As illustrated, all the phone numbers needs to be captured in an array. How do I accomplish that?

回答1:

Instead of your for-loop and the code inside it, use this:

arrayAllPhoneNumbers = mobClients.map({ clientPhoneNumber in     clientPhoneNumber.valueForKey("clientsMobilePhoneNumber") as! String }) messageVC.recipients = arrayAllPhoneNumbers

回答2:

let request = NSFetchRequest(entityName: "CLIENTS") let results = (try? managedContext.executeFetchRequest(request)) as? [NSManagedObject] ?? []  let numbers = results.flatMap { $0.valueForKey("clientsMobilePhoneNumber" as? String }

numbers is now an array of your phone numbers.

But like thefredelement said, it's better to subclass it so you can just cast it to that subclass and access the phone numbers directly.

转载请标明出处:iOS Core Data: Convert result of fetch request to an array

文章来源: iOS Core Data: Convert result of fetch request to an array

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