How can I reload a table view? Xcode 11

Question

I am currently trying to add a row into the tableView, My code to add the view is as follows

     @IBAction func done(segue:UIStoryboardSegue) {
        let newContact = segue.source as! NewContactViewController
        FirstName = newContact.firstName
        LastName = newContact.lastName
           print("Adding the name: " + FirstName + " " + LastName + " to the nameArry")
        nameArry.append(FirstName + " " + LastName)
        print("Added " + nameArry[nameArry.count - 1] + " to name array")
        
        let indexPath = IndexPath(row: myContact.count + contacts.count - 1, section: 0) // Set the indexPath to the lowest part of the array
        
        tableView.beginUpdates() // Starts the update
        tableView.insertRows(at: [indexPath], with: .automatic) // Insert row at the lowest part of the table
        tableView.endUpdates() // Ends the update
        
        newContact.firstName = "" // Clears the variable "firstName"
        newContact.lastName = "" // Clears the variable "lastName"
        view.endEditing(true) // Disables Editing, saw it on youtube.
    }

I used myContact.count + contacts.count for the indexPath because thats what I use on my tableView

    // Get Number of items in table
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return (myContact.count + contacts.count)
    }

I get the following error:

Thread 1: Exception: "attempt to insert row 4 into section 0, but there are only 4 rows in section 0 after the update" 

Answer 1

I figured it out, I wasn't getting the accurate count, since I wasn't appending anything to the contacts array.

contacts.append(Contacts(MyContact: nameArry[nameArry.count - 1], Me: ""))

let indexPath = IndexPath(row: myContact.count + contacts.count - 1, section: 0)