When should regular expressions be preferred over str_ireplace for text manipulation in PHP?

Regular expressions should be preferred over str_ireplace when you need more advanced pattern matching and manipulation of text. Regular expressions offer more flexibility and power in searching and replacing text based on specific patterns, making them ideal for complex text manipulation tasks. On the other hand, str_ireplace is simpler and more straightforward for basic case-insensitive string replacements.

// Example of using regular expressions for text manipulation
$text = "Hello, World!";
$pattern = "/hello/i";
$replacement = "Hi";
$new_text = preg_replace($pattern, $replacement, $text);
echo $new_text; // Output: Hi, World!