How can the PHP code be optimized to improve performance and avoid common pitfalls?

To optimize PHP code for improved performance and avoid common pitfalls, consider the following techniques: 1. Use proper data structures and algorithms to efficiently handle data processing. 2. Minimize database queries by using caching mechanisms like Memcached or Redis. 3. Avoid using nested loops and excessive recursion which can lead to performance bottlenecks. Example PHP code snippet demonstrating the use of caching with Memcached:

// Connect to Memcached server
$memcached = new Memcached();
$memcached->addServer('localhost', 11211);

// Check if data exists in cache
$data = $memcached->get('cached_data');

if (!$data) {
    // If data is not in cache, fetch from database
    $data = fetchDataFromDatabase();

    // Store data in cache for future use
    $memcached->set('cached_data', $data, 3600); // Cache for 1 hour
}

// Use the fetched data
echo $data;