Deleting items in Core Data - ios

Question

Before deleteData() method was called, I've verified that there are two instances in my Core Data. Now I need to delete one away. I referred to this tutorial to delete my core data.
I managed to copy the first NSManagedObject instance through let person = people[0] as! NSManagedObject through this code, but app terminated on this line managedContext.delete(person).
The error faced was Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSManagedObjectContext delete:]: unrecognized selector sent to instance 0x7fefe28092e0'
func deleteData() {
var people = [Particulars]()
let fetchRequest = NSFetchRequest(entityName: "Particulars")
let appDel = UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = appDel.managedObjectContext
do {
people = try managedContext.executeFetchRequest(fetchRequest) as! [Particulars]
do {
let person = people[0] as! NSManagedObject
managedContext.delete(person)
try managedContext.save()
} catch let error as NSError {
print("Could not delete data \(error)")
}
} catch let error as NSError
{
print("Could not fetch data \(error)")
}
}

Answer 1

The proper call is not delete, but deleteObject for NSManagedObjectContext.
Also note that it is more readable to write person.first rather than people[0], but it is of course a matter of taste.
I think let person = people[0] as! NSManagedObject is problematic, because
It is not safe and would crash if there are no search results. Use if let person = people.first...
The downcast from Particulars to NSManagedObject also does not make sense. You have already performed a cast when getting the search results.