php获取中文字符拼音首字母ASCII

场景：对中文字符串进行排序<?php

class demo
{
    public function __construct()
    {

    }

    /**
     * @todo 获取中文字符串的字符首字母ascii
     * @param $string
     * @param int $default_length
     * @return float|int
     */
    public function chinese_alphabet_ascii($string, $default_length = 3)
    {
        $string_length = mb_strlen($string);
        $number = 0;

        for ($i = 0; $i < $string_length; $i++) {
　　　　　　　$number = $number * 100 + $this->chinese_initials(mb_substr($string, $i, $i + 1));
　　　　　　　if($i === $default_length - 1) breack;
        }

        for ($j = $string_length; $j < $default_length; $j++) {
            $number *= 100;
        }

        return $number;
    }

    /**
     * @todo 获取汉字拼音首字母 - ASCII
     * @param $character
     * @return int
     */
    public function chinese_initials($character) {
        $ascii = ord($character);

        if ($ascii > 127) {
            $unicode = iconv("UTF-8", "GB2312", $character);
            $ascii = ord($unicode{0}) * 256 + ord($unicode{1}) - 65536;
        }

        switch ($ascii) {
            // 0 ~ 9
            case $ascii >= 48 && $ascii <= 57 :
                $result_ascii = $ascii;
                break;
            // A ~ Z
            case $ascii >= 65 && $ascii <= 90 :
                $result_ascii = $ascii;
                break;
            // a ~ z
            case $ascii >= 97 && $ascii <= 122 :
                $result_ascii = $ascii - 32;
                break;
            // 汉字字母
            case $ascii >= -20319 && $ascii <= -20284:
                $result_ascii = 65;
                break;
            case $ascii >= -20283 && $ascii <= -19776:
                $result_ascii = 66;
                break;
            case $ascii >= -19775 && $ascii <= -19219:
                $result_ascii = 67;
                break;
            case $ascii >= -19218 && $ascii <= -18711:
                $result_ascii = 68;
                break;
            case $ascii >= -18710 && $ascii <= -18527:
                $result_ascii = 69;
                break;
            case $ascii >= -18526 && $ascii <= -18240:
                $result_ascii = 70;
                break;
            case $ascii >= -18239 && $ascii <= -17923:
                $result_ascii = 71;
                break;
            case $ascii >= -17922 && $ascii <= -17418:
                $result_ascii = 72;
                break;
            case $ascii >= -17417 && $ascii <= -16475:
                $result_ascii = 74;
                break;
            case $ascii >= -16474 && $ascii <= -16213:
                $result_ascii = 75;
                break;
            case $ascii >= -16212 && $ascii <= -15641:
                $result_ascii = 76;
                break;
            case $ascii >= -15640 && $ascii <= -15166:
                $result_ascii = 77;
                break;
            case $ascii >= -15165 && $ascii <= -14923:
                $result_ascii = 78;
                break;
            case $ascii >= -14922 && $ascii <= -14915:
                $result_ascii = 79;
                break;
            case $ascii >= -14914 && $ascii <= -14631:
                $result_ascii = 80;
                break;
            case $ascii >= -14630 && $ascii <= -14150:
                $result_ascii = 81;
                break;
            case $ascii >= -14149 && $ascii <= -14091:
                $result_ascii = 82;
                break;
            case $ascii >= -14090 && $ascii <= -13319:
                $result_ascii = 83;
                break;
            case $ascii >= -13318 && $ascii <= -12839:
                $result_ascii = 84;
                break;
            case $ascii >= -12838 && $ascii <= -12557:
                $result_ascii = 87;
                break;
            case $ascii >= -12556 && $ascii <= -11848:
                $result_ascii = 88;
                break;
            case $ascii >= -11847 && $ascii <= -11056:
                $result_ascii = 89;
                break;
            case $ascii >= -11055 && $ascii <= -10247:
                $result_ascii = 90;
                break;
            default:
                $result_ascii = 91;
        }
        return $result_ascii;
    }
}

补充：&& 、||  与 and、or 的优先级：

优先级：&& > || > and > or

1. 单独的两个表达参与运算，&&与and、||与or运算结果一样；

2.多个表达式参与运算时，注意优先级问题，例如：$a || $b and $c || $d 相当于 ($a || $b) and ($c || $d) 。