使用php来批量获取汉字、数字、英文的首字母

使用php来批量获取汉字、数字、英文的首字母，可以来用作字母和数字英文等混合字符串进行按首字母排序。

多维数组的排序链接：https://ijuer.com/blog/139.html

<?php
if (ord($title) > 128) { //汉字开头
    echo $letter = getfirstchar($title);
} else if (ord($title) >= 48 and ord($title) <= 57) { //数字开头
    echo $letter = iconv_substr($title, 0, 1, 'utf-8');
} else if (ord($title) >= 65 and ord($title) <= 90) { //大写英文开头
    echo $letter = iconv_substr($title, 0, 1, 'utf-8');
} else if (ord($title) >= 97 and ord($title) <= 122) { //小写英文开头
    echo $letter = iconv_substr($title, 0, 1, 'utf-8');
}
function getfirstchar($s0) {
    $s = iconv("UTF-8", "gb2312", $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 false;
}
?>