查找最内部括号内的字符串 [英] Find String Inside Outermost Parenthesis

问题描述

说我有一个包含多个集合和嵌套括号的字符串。我想只提取遇到的第一个括号中的字符串，包括它包含的任何嵌套括号。

Say that I have a string which contains both multiple sets and nesting of parenthesis. I want to extract only the string in the first parenthesis encountered, including whatever nested parenthesis it contains.

例如：

这是（可能）测试（可能不是）

this (is(maybe)) a test (and maybe not)

提取：

是（可能）

is(maybe)

我相信这可以在不使用正则表达式的情况下完成，我可以很容易地做到。

I believe this can be accomplished without the use of regexes, by which I can easily do it.

所以我的问题是如何可以完成 / em> regexes？

So my question is how can this be accomplished without regexes?

推荐答案

Lest伪代码是我自己使用标准算法：

Lest pseudo code be the only answer I've taken it upon myself to answer this using standard algorithms:

const string foo{ "this (is(maybe)) a test (and maybe not)" };
const auto start = find(foo.cbegin(), foo.cend(), '(');
const auto finish = find_if(start, foo.cend(), [](char i){
    static auto count = 0;

    if (i == '('){
        count++;
    }
    else if (i == ')'){
        count--;
    }
    return count <= 0; });

从这里，如果开始和完成都不是 foo.cend（）字符串是有效的，可以从 string（next（start），finish）获取 href =http://ideone.com/5Nkx8p =nofollow> Live Example ）。

From here, if both start and finish are not foo.cend() the string is valid and can be obtained from string(next(start), finish) (Live Example).

这可能是一个很好的解决方案，因为有在C + +。我想这只是一厢情愿地认为有东西在那里匹配括号和找到值。

It's possible that this is as good a solution as there is in C++. I guess it is just wishful thinking that there's something out there to match parentheses and find the value.

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