php 字符串 驼峰改为下划线

* application/common/utils/Str.PHP

<?PHP

namespace app\common\utils;


class Str
{
    /**
     * 驼峰命名转下划线命名
     * @param $str
     * @return string
     */
    public static function toUnderscore($str) {
        $s = "";
        $c = ord($str[0]);
        if (65 <= $c && $c < 92) {
            $s .= chr($c + 32);
        } else {
            $s .= $str[0];
        }
        $n = strlen($str);
        for ($i = 1; $i < $n; $i++) {
            $c = ord($str[$i]);
            if (65 <= $c && $c < 92) {
                $s .= "_".chr( $c + 32 );
            } else {
                $s .= $str[$i];
            }
        }
        return $s;
    }
}

* application/index/controller/Index.PHP

<?PHP
namespace app\index\controller;

use app\common\utils\Str;

class Index
{
    public function index()
    {
        return '<style type="text/css">*{ padding: 0; margin: 0; } .think_default_text{ padding: 4px 48px;} a{color:#2E5CD5;cursor: pointer;text-decoration: none} a:hover{text-decoration:underline; } body{ background: #fff; font-family: "Century Gothic","Microsoft yahei"; color: #333;font-size:18px} h1{ font-size: 100px; font-weight: normal; margin-bottom: 12px; } p{ line-height: 1.6em; font-size: 42px }</style><div style="padding: 24px 48px;"> <h1>:)</h1><p> ThinkPHP V5<br/><span style="font-size:30px">十年磨一剑 - 为API开发设计的高性能框架</span></p><span style="font-size:22px;">[ V5.0 版本由 <a href="http://www.qiniu.com" target="qiniu">七牛云</a> 独家赞助发布 ]</span></div><script type="text/javascript" src="https://tajs.qq.com/stats?sId=9347272" charset="UTF-8"></script><script type="text/javascript" src="https://e.topthink.com/Public/static/client.js"></script><think id="ad_bd568ce7058a1091"></think>';
    }

    /**
     * http://hy.cn/index/index/test
     * @return string
     */
    public function test() {
        // return "<p>Hello World!</p>";
        echo Str::toUnderscore("HelloWorldBounjour").'<br />';
        echo Str::toUnderscore("shalomANiYana").'<br />';
        echo Str::toUnderscore("Controller");
    }
}

访问 http://hanyuan.fun/index.php/index/index/test

输出：

hello_world_bounjour
shalom_a_ni_yana
controller