Function to escape regex patterns before applied in PHP

In PHP, the preg_quote() function can be used to escape regular expression patterns before they are applied.

The preg_quote() function accepts two parameters: the first parameter is the string to be escaped, and the second parameter is an optional delimiter character that can be used to specify a custom delimiter for the regular expression pattern.

Here is an example of how to use preg_quote() function:

$pattern = "/[a-z]+/";
$escaped_pattern = preg_quote($pattern, '/');
echo $escaped_pattern; // Output: /\[a\-z\]\+/

In the above example, the regular expression pattern /[a-z]+/ is passed as the first parameter to preg_quote() function. The second parameter is the delimiter character / which is used to specify the custom delimiter for the regular expression pattern. The output of the preg_quote() function is the escaped pattern /\[a\-z\]\+/.

Note that the preg_quote() function escapes all characters that have special meaning in regular expressions, including the delimiter character. If you want to use a custom delimiter character, you need to specify it as the second parameter to preg_quote() function.