handling_duplicates.php

<?php

function index_by(array $arr, $getKey) {
  return array_combine(array_map($getKey, $arr), $arr);
}

$emails = ['ben@vtdesignworks.com', 'bruce@ksefocus.com'];
$emailAddresses = $emailAddressRepository->findByEmails($emails);
$emailAddressesByEmail = index_by(
  $emailAddresses,
  function(EmailAddress $address) { return $address->getEmail(); }
);
// $emailsAddressesByEmail is now an array of $email => EmailAddress
// For any that weren't found, create new instances
foreach ($emails as $email) {
  if (isset($emailAddresses[$email])) {
    continue;
  }
  $emailAddresses[$email] = new EmailAddress($email);
}

foreach ($email as $email) {
  $alert->addEmail($emailAddresses[$email]);
}