php 中文字符串首字母函数的获取

 function chineseFirst($str)      {      $str= iconv("UTF-8","gb2312", $str);//如果程序是gbk的，此行就要注释掉      //判断字符串是否全都是中文 （PS：^_^不错的php学习交流群：276167802，验证：csl，有兴趣的话可以加入进来一起讨论）      if (preg_match("/^[/x7f-/xff]/", $str))      {      $fchar=ord($str{0});      if($fchar>=ord("A") and $fchar<=ord("z") )return strtoupper($str{0});      $a = $str;      $val=ord($a{0})*256+ord($a{1})-65536;      if($val>=-20319 and $val<=-20284)return "A";      if($val>=-20283 and $val<=-19776)return "B";      if($val>=-19775 and $val<=-19219)return "C";      if($val>=-19218 and $val<=-18711)return "D";      if($val>=-18710 and $val<=-18527)return "E";      if($val>=-18526 and $val<=-18240)return "F";      if($val>=-18239 and $val<=-17923)return "G";      if($val>=-17922 and $val<=-17418)return "H";      if($val>=-17417 and $val<=-16475)return "J";      if($val>=-16474 and $val<=-16213)return "K";      if($val>=-16212 and $val<=-15641)return "L";      if($val>=-15640 and $val<=-15166)return "M";      if($val>=-15165 and $val<=-14923)return "N";      if($val>=-14922 and $val<=-14915)return "O";      if($val>=-14914 and $val<=-14631)return "P";      if($val>=-14630 and $val<=-14150)return "Q";      if($val>=-14149 and $val<=-14091)return "R";      if($val>=-14090 and $val<=-13319)return "S";      if($val>=-13318 and $val<=-12839)return "T";      if($val>=-12838 and $val<=-12557)return "W";      if($val>=-12556 and $val<=-11848)return "X";      if($val>=-11847 and $val<=-11056)return "Y";      if($val>=-11055 and $val<=-10247)return "Z";      } else      {      return false;      }      }