以下是一个将中文字符串转换为首字母的示例函数：
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functiongetFirstChar($str){$firstChar=strtoupper(substr($str,0,1));$str=iconv("UTF-8","gb2312",$str);$asc=ord(substr($str,0,1)) *256+ord(substr($str,1,1)) -65536;if($asc>= -20319&&$asc<= -20284) {return'A'; }if($asc>= -20283&&$asc<= -19776) {return'B'; }if($asc>= -19775&&$asc<= -19219) {return'C'; }if($asc>= -19218&&$asc<= -18711) {return'D'; }if($asc>= -18710&&$asc<= -18527) {return'E'; }if($asc>= -18526&&$asc<= -18240) {return'F'; }if($asc>= -18239&&$asc<= -17923) {return'G'; }if($asc>= -17922&&$asc<= -17418) {return'H'; }if($asc>= -17417&&$asc<= -16475) {return'J'; }if($asc>= -16474&&$asc<= -16213) {return'K'; }if($asc>= -16212&&$asc<= -15641) {return'L'; }if($asc>= -15640&&$asc<= -15166) {return'M'; }if($asc>= -15165&&$asc<= -14923) {return'N'; }if($asc>= -14922&&$asc<= -14915) {return'O'; }if($asc>= -14914&&$asc<= -14631) {return'P'; }if($asc>= -14630&&$asc<= -14150) {return'Q'; }if($asc>= -14149&&$asc<= -14091) {return'R'; }if($asc>= -14090&&$asc<= -13319) {return'S'; }if($asc>= -13318&&$asc<= -12839) {return'T'; }if($asc>= -12838&&$asc<= -12557) {return'W'; }if($asc>= -12556&&$asc<= -11848) {return'X'; }if($asc>= -11847&&$asc<= -11056) {return'Y'; }if($asc>= -11055&&$asc<= -10247) {return'Z'; }return$firstChar;}
使用示例：
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echogetFirstChar('你好世界');// 输出 N
请注意，这种方法只适用于简体中文，对于繁体中文或其他语言可能需要进行修改。
