如何在标准字符串中搜索/查找和替换?

为什么不实现自己的替换呢?

void myReplace(std::string& str,
               const std::string& oldStr,
               const std::string& newStr)
{
  std::string::size_type pos = 0u;
  while((pos = str.find(oldStr, pos)) != std::string::npos){
     str.replace(pos, oldStr.length(), newStr);
     pos += newStr.length();
  }
}

#include <boost/algorithm/string.hpp> // include Boost, a C++ library
...
std::string target("Would you like a foo of chocolate. Two foos of chocolate?");
boost::replace_all(target, "foo", "bar");

这是 the official documentation 关于RePasy-ALL。

在C++ 11中,您可以通过调用 regex_replace :

#include <string>
#include <regex>

using std::string;

string do_replace( string const & in, string const & from, string const & to )
{
  return std::regex_replace( in, std::regex(from), to );
}

string test = "Remove all spaces";
std::cout << do_replace(test, " ", "") << std::endl;

输出:

Removeallspaces

为什么不返回修改后的字符串?

std::string ReplaceString(std::string subject, const std::string& search,
                          const std::string& replace) {
    size_t pos = 0;
    while((pos = subject.find(search, pos)) != std::string::npos) {
         subject.replace(pos, search.length(), replace);
         pos += replace.length();
    }
    return subject;
}

如果需要性能,这里有一个修改输入字符串的优化函数,它不会创建字符串的副本:

void ReplaceStringInPlace(std::string& subject, const std::string& search,
                          const std::string& replace) {
    size_t pos = 0;
    while((pos = subject.find(search, pos)) != std::string::npos) {
         subject.replace(pos, search.length(), replace);
         pos += replace.length();
    }
}

测验:

std::string input = "abc abc def";
std::cout << "Input string: " << input << std::endl;

std::cout << "ReplaceString() return value: " 
          << ReplaceString(input, "bc", "!!") << std::endl;
std::cout << "ReplaceString() input string not changed: " 
          << input << std::endl;

ReplaceStringInPlace(input, "bc", "??");
std::cout << "ReplaceStringInPlace() input string modified: " 
          << input << std::endl;

输出:

Input string: abc abc def
ReplaceString() return value: a!! a!! def
ReplaceString() input string not modified: abc abc def
ReplaceStringInPlace() input string modified: a?? a?? def

我的模板化内联就地查找和替换:

template<class T>
int inline findAndReplace(T& source, const T& find, const T& replace)
{
    int num=0;
    typename T::size_t fLen = find.size();
    typename T::size_t rLen = replace.size();
    for (T::size_t pos=0; (pos=source.find(find, pos))!=T::npos; pos+=rLen)
    {
        num++;
        source.replace(pos, fLen, replace);
    }
    return num;
}

它返回被替换的项数的计数(如果要连续运行此项,则使用此项等)。要使用它:

std::string str = "one two three";
int n = findAndReplace(str, "one", "1");

最简单的方法(提供接近你所写内容的内容)是使用 Boost.Regex ,具体地说 regex_replace .

std::string内置find()和replace()方法,但它们在处理索引和字符串长度时更麻烦。

我相信这会奏效的。 它以const char*作为参数。

//params find and replace cannot be NULL
void FindAndReplace( std::string& source, const char* find, const char* replace )
{
   //ASSERT(find != NULL);
   //ASSERT(replace != NULL);
   size_t findLen = strlen(find);
   size_t replaceLen = strlen(replace);
   size_t pos = 0;

   //search for the next occurrence of find within source
   while ((pos = source.find(find, pos)) != std::string::npos)
   {
      //replace the found string with the replacement
      source.replace( pos, findLen, replace );

      //the next line keeps you from searching your replace string, 
      //so your could replace "hello" with "hello world" 
      //and not have it blow chunks.
      pos += replaceLen; 
   }
}

#include <iostream>
#include <string>

#include <boost/algorithm/string.hpp>
#include <boost/tokenizer.hpp>
#include <boost/foreach.hpp>

using namespace boost::algorithm;
using namespace std;
using namespace boost;

void highlighter(string terms, string text) {

    char_separator<char> sep(" ");
    tokenizer<char_separator<char> > tokens(terms, sep);

    BOOST_FOREACH(string term, tokens) {
        boost::replace_all(text, term, "<b>" + term + "</b>");
    }   
    cout << text << endl;
}

int main(int argc, char **argv)
{
    cout << "Search term highlighter" << endl;
    string text("I love boost library, and this is a test of boost library!");
    highlighter("love boost", text);
}

我 爱 促进 图书馆,这是对 促进 图书馆!

// Replace all occurrences of searchStr in str with replacer
// Each match is replaced only once to prevent an infinite loop
// The algorithm iterates once over the input and only concatenates 
// to the output, so it should be reasonably efficient
std::string replace(const std::string& str, const std::string& searchStr, 
    const std::string& replacer)
{
    // Prevent an infinite loop if the input is empty
    if (searchStr == "") {
        return str;
    }

    std::string result = "";
    size_t pos = 0;
    size_t pos2 = str.find(searchStr, pos);

    while (pos2 != std::string::npos) {
        result += str.substr(pos, pos2-pos) + replacer;
        pos = pos2 + searchStr.length();
        pos2 = str.find(searchStr, pos);
    }

    result += str.substr(pos, str.length()-pos);
    return result;
}

#include <string>

using std::string;

void myReplace(string& str,
               const string& oldStr,
               const string& newStr) {
  if (oldStr.empty()) {
    return;
  }

  for (size_t pos = 0; (pos = str.find(oldStr, pos)) != string::npos;) {
    str.replace(pos, oldStr.length(), newStr);
    pos += newStr.length();
  }
}

检查oldstr是否为空很重要。如果由于任何原因,该参数为空,您将陷入无限循环。

但是,如果可以的话,请使用经过考验的C++ 11或Boost解决方案。