Online PHP editor | refs for vDNLo

<?php declare(strict_types = 1); class HelloWorld { public static function createData(): array { $data = [ [ 'title' => 'Title 1', 'start_at' => new DateTime(), ], [ 'title' => 'Title 2', 'start_at' => new DateTime(), ], [ 'title' => 'Title 3', 'start_at' => new DateTime(), ], ]; foreach ($data as $key => &$row) { $row['end_at'] = $data[$key + 1]['start_at'] ?? null; } return array_filter($data, function ($row): bool { return $row['end_at'] !== null; }); } } print_R(HelloWorld::createData());