php实现获取汉字的首字母实例

//取汉字的asc区间然后返回汉字首字母了,代码如下:
header("Content-type: text/html; charset=utf-8"); 
    function getfirstchar($s0){     
        $fchar = ord($s0{0});  
        if($fchar >= ord("A") and $fchar <= ord("z") ){
            return strtoupper($s0{0});  
        }
        
        $s1 = iconv("UTF-8","gb2312", $s0);  
        $s2 = iconv("gb2312","UTF-8", $s1); 
        
        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 $asc <= -17418) return "I";  
        if($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;  
    }  
       
       
    function pinyin1($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;  
    }  
    echo "这是中文字符串<br/>";  
    echo pinyin1('这是中文字符串');