Are there any common mistakes to avoid when using regex in PHP?

One common mistake to avoid when using regex in PHP is using incorrect delimiters. The delimiters in regex help define the start and end of the pattern, and using the wrong delimiter can lead to unexpected results. To fix this issue, make sure to use appropriate delimiters such as '/' or '#' at the beginning and end of your regex pattern.

// Incorrect delimiter usage
$pattern = "/hello/";

// Correct delimiter usage
$pattern = "#hello#";