深入了解高级PHP正则表达式：发现并应用强大的匹配和替换技巧

$email = "example@example.com";
$pattern = '/(w+)@(w+.com)/';
preg_match($pattern, $email, $matches);

$username = $matches[1];
$domain = $matches[2];

echo "Username: " . $username . "
";
echo "Domain: " . $domain . "
";

Username: example
Domain: example.com

$string = "Price: $19.99";
$pattern = '/Price: $(d+(?:.d+)?)/';
preg_match($pattern, $string, $matches);

$price = $matches[1];

echo "Price: $" . $price . "
";

Price: $19.99

$string = "Hello world, my name is PHP";
$pattern = '/(w+)/';
$newString = preg_replace_callback($pattern, function($matches) {
    return strrev($matches[0]);
}, $string);

echo $newString . "
";

olleH dlrow, ym eman si PHP

$html = "<img src='image.jpg'> <img src='image.png'>";
$pattern = '/(?<=<img src=')(.*?)(?='>)/';
$newHtml = preg_replace($pattern, 'new_image.jpg', $html);

echo $newHtml . "
";

<img src='new_image.jpg'> <img src='new_image.jpg'>