如何在PHP中编写正则表达式以删除特殊字符？

<?php
function removeSpecialCharacters($string) {
    // 使用正则表达式匹配特殊字符
    $pattern = '/[^a-zA-Z0-9\s]/';

    // 使用空字符串替换特殊字符
    $result = preg_replace($pattern, '', $string);

    return $result;
}

$string = "Hello,@#World!$%^";
$result = removeSpecialCharacters($string);

echo "Original String: " . $string . PHP_EOL;
echo "String without special characters: " . $result . PHP_EOL;
?>