C ++在单个遍中替换字符串中的多个字符串 [英] C++ replace multiple strings in a string in a single pass

问题描述

给定以下字符串，Hi〜+和^ *。^ *仍在飞来飞去〜+？

我想用Bobby替换所有出现的〜+和^ *和Danny，所以字符串变成：

I want to replace all occurrences of "~+" and "^*" with "Bobby" and "Danny", so the string becomes:

你好鲍比和丹尼，丹尼依然在鲍比飞吗？

我不想调用Boost替换函数两次来替换两个不同值的出现。

I would prefer not to have to call Boost replace function twice to replace the occurrences of the two different values.

推荐答案

我设法使用Boost.Iostreams实现所需的替换函数。具体来说，我使用的方法是使用正则表达式匹配要替换的过滤流。我不知道在gigabyte大小的文件的性能。你需要测试它当然。无论如何，这里是代码：

I managed to implement the required replacement function using Boost.Iostreams. Specifically, the method I used was a filtering stream using regular expression to match what to replace. I am not sure about the performance on gigabyte sized files. You will need to test it of course. Anyway, here's the code:

#include <boost/regex.hpp>
#include <boost/iostreams/filter/regex.hpp>
#include <boost/iostreams/filtering_stream.hpp>
#include <iostream>

int main()
{
   using namespace boost::iostreams;

   regex_filter filter1(boost::regex("~\\+"), "Bobby");
   regex_filter filter2(boost::regex("\\^\\*"), "Danny");

   filtering_ostream out;
   out.push(filter1);
   out.push(filter2);
   out.push(std::cout);

   out << "Hi ~+ and ^*. Is ^* still flying around ~+?" << std::endl;

   // for file conversion, use this line instead:
   //out << std::cin.rdbuf();
}

上面的图片Hi Bobby和Danny Danny仍然在Bobby附近飞行？运行时，就像预期的那样。

The above prints "Hi Bobby and Danny. Is Danny still flying around Bobby?" when run, just like expected.

如果你决定测量它。

丹尼尔

编辑：我只是意识到 regex_filter 需要将整个字符序列读入内存，这对于千兆字节大小的输入来说是无用的。哦，好...

I just realized that regex_filter needs to read the entire character sequence into memory, making it pretty useless for gigabyte-sized inputs. Oh well...

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