How to make alphabetical section with contacts in tableView in swift - swift

Question

I'm new to Swift and I have arrays made with CNContact(familyName, givenName, phoneNumber).
I'd like to make name contacts alphabetical order and group them in sections in order to put them in the "titleForHeaderInSection" as below.
Does anyone know how to group and put it into titleForHeaderInSection??
struct AddressModel {
let nameAndPhone: [AddressContact]
}
struct AddressContact {
let contact: CNContact
}
class AddressViewController: UITableViewController {
var addressArray = [AddressModel]()
private func fetchContacts() {
print("Attempting to fetch contacts today")
let store = CNContactStore()
store.requestAccess(for: .contacts) { (granted, err) in
if let err = err {
print("Failed to request access:", err)
return
}
if granted {
let keys = [CNContactFormatter.descriptorForRequiredKeys(for: .fullName), CNContactPhoneNumbersKey] as [Any]
let request = CNContactFetchRequest(keysToFetch: keys as! [CNKeyDescriptor])
request.sortOrder = CNContactSortOrder.userDefault
do {
var addressContact = [AddressContact]()
try store.enumerateContacts(with: request, usingBlock: { (contact, stop) in
addressContact.append(AddressContact(contact: contact))
})
let nameAndPhone = AddressModel(nameAndPhone: addressContact)
self.addressArray = [nameAndPhone]
} catch let err {
print("Failed to enumerate contacts:", err)
}
} else {
print("Access denied..")
}
}
}
override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return "Section \(section)"
}
override func numberOfSections(in tableView: UITableView) -> Int {
return self.addressArray.count
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.addressArray[section].nameAndPhone.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
let nameAndPhone = addressArray[indexPath.section].nameAndPhone[indexPath.row]
let fullName = nameAndPhone.contact.familyName + nameAndPhone.contact.givenName
cell.textLabel?.text = fullName
return cell
}

Answer 1

Try this
func sectionIndexTitles(for tableView: UITableView) -> [String]? {
// ...
}

Answer 2

For sorting section title try the closure:
sectionTitle = sectionTitle.sorted(by: { $0 < $1 }) // First argument smaller then second argument.