从特定字符序列的最后一次出现开始删除所有字符 [英] Remove all characters starting from last occurrence of specific sequence of characters

问题描述

我正在解析一些电子邮件.我认为移动邮件，iPhone和iPod touch会附加一个签名作为单独的边界，从而使其易于删除.并非所有邮件客户端都这样做，仅使用'-'作为签名定界符.

I am parsing out some emails. Mobile Mail, iPhone and I assume iPod touch append a signature as a separate boundary, making it simple to remove. Not all mail clients do, and just use '--' as a signature delimiter.

我需要从字符串中剔除'-'，但仅是最后一次出现.

I need to chop off the '--' from a string, but only the last occurrence of it.

样本副本

 hello, this is some email copy-- check this out
 --
 Tom Foolery

我考虑过拆分'-'，删除最后一部分，我会得到，但是 explode()和 split()似乎都没有返回如果没有匹配项，让我知道它是否做了任何事情，都是非常有价值的.

I thought about splitting on '--', removing the last part, and I would have it, but explode() and split() neither seem to return great values for letting me know if it did anything, in the event there is not a match.

我无法获得 preg_replace()跨越多行.我已经将所有行尾标准化为 \ n .

I can not get preg_replace() to go across more than one line. I have standardized all line endings to \n.

以 hello结尾的最佳建议是什么，这是一些电子邮件副本-检查一下，不这样做，在某些情况下没有签名，当然也有在某些情况下我无法涵盖所有​​情况.

What is the best suggestion to end up with hello, this is some email copy-- check this out, taking not, there will be cases where there is no signature, and there are of course going to be cases where I can not cover all the cases.

推荐答案

我认为，为了更加防弹，我将采用非正则表达式路线

I think in the interest of being more bulletproof, I will take the non regex route

        echo substr($body, 0, strrpos($body, "\n--"));

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