Online PHP editor | output for kn7II

<?php function getGreeting(MapInterface $user): string { $fullName = []; $fullNameSegments = ['first_name', 'last_name']; foreach ($fullNameSegments as $segment) { if ($user->has($segment)) { $fullName[] = $user->get($segment); } } return implode(' ', $fullName); } interface MapInterface { public function get(string $key); public function has(string $key): bool; } class Map implements MapInterface { protected $data; public function __construct(array $data) { $this->data = $data; } public function get(string $key) { if (!array_key_exists($key, $this->data)) { throw new RangeException(sprintf('Key %1$s not found', $key)); } return $this->data[$key]; } public function has(string $key): bool { return array_key_exists($key, $this->data); } } $user = new Map([ 'first_name' => 'Xedin', 'last_name' => 'Unknown', 'id' => '12345', ]); assert($user instanceof MapInterface); echo getGreeting($user);