strrev

<?php/** * Reverse a miltibyte string. * * @param string $string The string to be reversed. * @param string|null $encoding The character encoding. If it is omitted, the internal character encoding value *     will be used. * @return string The reversed string */function mb_strrev(string $string, string $encoding = null): string{    $chars = mb_str_split($string, 1, $encoding ?: mb_internal_encoding());    return implode('', array_reverse($chars));}?>It's faster and flexible than tianyiw function (comment #122953)

This function support utf-8 encoding, Human Language and Character Encoding Support:<?phpfunction mb_strrev($str){    $r = '';    for ($i = mb_strlen($str); $i>=0; $i--) {        $r .= mb_substr($str, $i, 1);    }    return $r;}echo mb_strrev("☆❤world"); // echo "dlrow❤☆"?>