PHP获取首字母笔记

方法如下：

 function getFirstChar($s0)
    {
        $fchar = ord($s0{0});
        if ($fchar >= ord("A") and $fchar <= ord("z")) return strtoupper($s0{0});
        $s1 = iconv("UTF-8", "GBK", $s0);
        $s2 = iconv("GBK", "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 $asc <= -17418) return "H";
        if ($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 null;
    }

参考：http://www.thinkphp.cn/topic/58452.html

来源：https://www.cnblogs.com/zqsb/p/11910052.html