如何在PHP中反转这些代码

$code = "这是要反转的代码";
$reversedCode = strrev($code);
echo $reversedCode;

$code = "这是要反转的代码";
$length = strlen($code);
for ($i = $length - 1; $i >= 0; $i--) {
    echo $code[$i];
}

$code = "这是要反转的代码";
$codeArray = str_split($code);
$reversedArray = array_reverse($codeArray);
$reversedCode = implode("", $reversedArray);
echo $reversedCode;