警告:preg_replace() [function.preg-replace]:编译失败:在偏移 1 处无需重复 [英] Warning: preg_replace() [function.preg-replace]: Compilation failed: nothing to repeat at offset 1

问题描述

有人可以帮忙调试这个错误吗?

Can someone help debug this error?

警告:preg_replace() [function.preg-replace]:编译失败:在偏移量 1 处无需重复

Warning: preg_replace() [function.preg-replace]: Compilation failed: nothing to repeat at offset 1

//Generate uid
    function gen_uid($len=40) {
        $hex = md5("what" . uniqid("", true));
        $pack = pack('H*', $hex);
        $tmp =  base64_encode($pack);
        $uid = preg_replace("#(*UTF8)[^A-Za-z0-9]#", "", $tmp);
        $len = max(4, min(128, $len));
        while (strlen($uid) < $len)
            $uid .= gen_uid(22);
        return substr($uid, 0, $len);
    }

这是什么原因造成的?这是PHP问题还是其他问题?该应用程序在我的本地机器上运行良好，但在服务器上运行不正常.

What causes this? Is it a PHP issue or something else? The application works fine on my local machine but not on the server.

推荐答案

* in regex 表示匹配前一个字符 0 次或多次，而 ( 开始捕获组.所以，* 没有什么可重复的，因为在 * 之前的是一个 (，它不能单独重复，因此这个警告.

* in regex means to match the previous character 0 or more times, while ( starts a capturing group. So, the * has nothing to repeat, since what comes before the * is a (, which cannot be repeated by itself, hence this warning.

要修复它，只需转义 *，就像这样:

To fix it, just escape the *, like so:

$uid = preg_replace("#(\*UTF8)[^A-Za-z0-9]#", "", $tmp);

这篇关于警告:preg_replace() [function.preg-replace]:编译失败:在偏移 1 处无需重复的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！