In what scenarios would it be beneficial to use functions like substr() in PHP, and what precautions should be taken to avoid unintended consequences?

When working with strings in PHP, using functions like substr() can be beneficial for extracting a specific portion of a string. This can be useful for tasks like truncating text, extracting substrings based on certain criteria, or manipulating string data. To avoid unintended consequences, it's important to ensure that the parameters passed to the substr() function are valid and within the bounds of the original string length.

// Example of using substr() to extract a portion of a string
$string = "Hello, World!";
$substring = substr($string, 0, 5); // Extract the first 5 characters
echo $substring; // Output: Hello