In my swift code I am attempting I would like to print the 3rd item in the array that was fetched from core data attribute atBATS. There is a sort descriptor in the code as well. Right now the code prints all the names just print the 3rd name. Assume that the array has 3 items in it.
func printStrings() {
let appD = UIApplication.shared.delegate as! AppDelegate
let context = appD.persistentContainer.viewContext
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Data")
request.returnsObjectsAsFaults = false
do {
let result = try context.fetch(request)
var retrievedData = [String]()
for data in result as! [NSManagedObject] {
let sort = NSSortDescriptor(key: "atBATS", ascending: false)
request.sortDescriptors = [sort]
if let value = data.value(forKey: "atBATS") as? String {
retrievedData.append((value))
}
}
print(retrievedData)
} catch {
print("Failed")
}
}
>Solution :
First of all do not name a custom struct or class Data. It can interfere with Foundation Data.
The sort descriptor is at the wrong place. It must be attached to the fetch request before fetching the data.
And you code is outdated. Use always the subclass of NSManagedObject. In the code below I name the class MyData
func printStrings() {
let appD = UIApplication.shared.delegate as! AppDelegate
let context = appD.persistentContainer.viewContext
let request : NSFetchRequest<MyData> = MyData.fetchRequest()
request.sortDescriptors = [NSSortDescriptor(key: "atBATS", ascending: false)]
do {
let result = try context.fetch(request)
let atBATS = result.map(\.atBATS)
if atBATS.count > 2 {
print(atBATS[2])
} else {
print("There are less than 3 items")
}
} catch {
print(error)
}
}