What resources or documentation can be helpful for PHP developers looking to improve their string handling skills?

PHP developers looking to improve their string handling skills can benefit from resources such as the official PHP documentation on string functions, online tutorials, and community forums where they can ask questions and learn from others. Additionally, practicing with string manipulation exercises and working on real-world projects can help developers enhance their skills.

// Example code snippet for improving string handling skills
$string = "Hello, World!";
$uppercaseString = strtoupper($string);
echo $uppercaseString;