Example of php regular expression escape characters

$str = preg_quote( " /d{3}(-d{4})/ " );
echo $str;
?>

result: /\d{3}(\-\d{4})/

Example 2:

$str = preg_quote( " /d{3}(-d{4})/ " , " 3 " );
echo $str;
?>

Results: /\d{3}(\-\d{4})/ The difference between these two examples: It’s the “3” in the red area. In the second example, “3” is also escaped. PHP escape character function PHP function to escape regular expression characters The problem of automatically adding escape characters when passing parameters in PHP form POST php anti-injection and form submission value escaping code Examples of character escaping methods in mysql statements Notes on php character escaping