php判断汉字首字母的简单例子

<?
function getfirstletter($string) {
   global $encoding;
   if($encoding=='UTF-8'){
    $string=string::hiconv($string,'gbk','utf-8');
   }
   $dict=array(
    'a'=>0xB0C4,'b'=>0xB2C0,'c'=>0xB4ED,'d'=>0xB6E9,
    'e'=>0xB7A1,'f'=>0xB8C0,'g'=>0xB9FD,'h'=>0xBBF6,
    'j'=>0xBFA5,'k'=>0xC0AB,'l'=>0xC2E7,'m'=>0xC4C2,
    'n'=>0xC5B5,'o'=>0xC5BD,'p'=>0xC6D9,'q'=>0xC8BA,
    'r'=>0xC8F5,'s'=>0xCBF9,'t'=>0xCDD9,'w'=>0xCEF3,
    'x'=>0xD1B8,'y'=>0xD4D0,'z'=>0xD7F9,
    );
   $letter = substr($string, 0, 1);
   $letter_ord = ord($letter);
   if($letter_ord >= 176 && $letter_ord <= 215){
    $num = '0x'.bin2hex(substr($string, 0, 2));
    foreach ($dict as $k=>$v){
     if($v>=$num) break;
    }
    return $k;
   }elseif(($letter_ord>64 && $letter_ord<91) || ($letter_ord>96 && $letter_ord<123)){
    return $letter;
   }elseif($letter>='0' && $letter<='9'){
    return $letter;
   }else{
    return '*';
   }
}
echo getfirstletter("你好，我是大山。");
?>