获取字符串的首拼

//获取汉字首拼---注意：汉字不以u，v首拼
    function getfirstchar($s0){
        $fchar = ord($s0{0});
        if($fchar >= ord("A") and $fchar <= ord("z") )return strtoupper($s0{0});
        $s1 = get_encoding($s0,'GB2312');
        $s2 = get_encoding($s1,'UTF-8');
        if($s2 == $s0){$s = $s1;}else{$s = $s0;}
        $asc = ord($s{0}) * 256 + ord($s{1}) - 65536;
        if($asc >= -20319 and $asc <= -20284) return "A";
        if($asc >= -20283 and $asc <= -19776) return "B";
        if($asc >= -19775 and $asc <= -19219) return "C";
        if($asc >= -19218 and $asc <= -18711) return "D";
        if($asc >= -18710 and $asc <= -18527) return "E";
        if($asc >= -18526 and $asc <= -18240) return "F";
        if($asc >= -18239 and $asc <= -17923) return "G";
        if($asc >= -17922 and $asc <= -17418) return "H";
        if($asc >= -17922 and $asc <= -17418) return "I";
        if($asc >= -17417 and $asc <= -16475) return "J";
        if($asc >= -16474 and $asc <= -16213) return "K";
        if($asc >= -16212 and $asc <= -15641) return "L";
        if($asc >= -15640 and $asc <= -15166) return "M";
        if($asc >= -15165 and $asc <= -14923) return "N";
        if($asc >= -14922 and $asc <= -14915) return "O";
        if($asc >= -14914 and $asc <= -14631) return "P";
        if($asc >= -14630 and $asc <= -14150) return "Q";
        if($asc >= -14149 and $asc <= -14091) return "R";
        if($asc >= -14090 and $asc <= -13319) return "S";
        if($asc >= -13318 and $asc <= -12839) return "T";
        if($asc >= -12838 and $asc <= -12557) return "W";
        if($asc >= -12556 and $asc <= -11848) return "X";
        if($asc >= -11847 and $asc <= -11056) return "Y";
        if($asc >= -11055 and $asc <= -10247) return "Z";
        return null;
    }

    //自动检测内容编码进行转换
    function get_encoding($data,$to){
        $encode_arr=array('UTF-8','ASCII','GBK','GB2312','BIG5','JIS','eucjp-win','sjis-win','EUC-JP');
        $encoded=mb_detect_encoding($data, $encode_arr);
        $data = mb_convert_encoding($data,$to,$encoded);
        return $data;
    }

    function getPinyin($zh){
        $ret = "";
        $s1 = iconv("UTF-8","gb2312", $zh);
        $s2 = iconv("gb2312","UTF-8", $s1);
        if($s2 == $zh){$zh = $s1;}
        for($i = 0; $i < strlen($zh); $i++){
            $s1 = substr($zh,$i,1);
            $p = ord($s1);
            if($p > 160){
                $s2 = substr($zh,$i++,2);
                $ret .= getfirstchar($s2);
            }else{
                $ret .= $s1;
            }
        }
        return $ret;
    }

$str = '你好';
echo getPinyin($str);    // NH