PHP uses regular expressions to scrape matching web pages and extract data.

You can use PHP's built-in functions. preg_match() Use this function for regular expression matching. Here is an example function: its first parameter is a regular expression, and its second parameter is the content to match:

function match_regex($pattern, $subject) {
  if (preg_match($pattern, $subject, $matches)) {
    return $matches;
  } else {
    return false;
  }
}

This function returns an array of matching results; if no matches are found, it returns `false`.

For example, if you want to determine whether a string is a valid email address, you can call this function as follows:

$pattern = '/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/';
$subject = 'example@example.com';
$result = match_regex($pattern, $subject);

if ($result) {
  echo "匹配成功！";
} else {
  echo "匹配失败！";
}

In this example, the regular expression $pattern Matches the email address format; variable $subject Contains the content to match – Function match_regex() Returns an array of matching results or `false`.