php取出字符串（包括汉字）首字母函数

<?php

//取出首字母函数

function getfirstchar($s0){ 

if(ord($s0)>="1" and ord($s0)<=ord("z") )   { return strtoupper($s0); } 

//$s=iconv("UTF-8","gb2312", $s0); 如果需要转换为utf-8的话

$s=$s0;//无需转换的情况

$asc=ord($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>=-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 0; 

}

echo getfirstchar("你好");

?>