如何从std :: vector中创建std :: string< string&gt ;? [英] How to construct a std::string from a std::vector<string>?

问题描述

我想从 std :: vector< std :: string> std :: string c>。

I'd like to build a std::string from a std::vector<std::string>.

我可以使用 std :: stringsteam ，但想象有一个更短的方法：

I could use std::stringsteam, but imagine there is a shorter way:

std::string string_from_vector(const std::vector<std::string> &pieces) {
  std::stringstream ss;

  for(std::vector<std::string>::const_iterator itr = pieces.begin();
      itr != pieces.end();
      ++itr) {
    ss << *itr;
  }

  return ss.str();
}

我还可以如何做呢？

推荐答案

您可以使用 < numeric> 标题中的std :: accumulate（） 标准函数为 string s定义运算符+ ，返回其两个参数的串联）：

You could use the std::accumulate() standard function from the <numeric> header (it works because an overload of operator + is defined for strings which returns the concatenation of its two arguments):

#include <vector>
#include <string>
#include <numeric>
#include <iostream>

int main()
{
    std::vector<std::string> v{"Hello, ", " Cruel ", "World!"};
    std::string s;
    s = accumulate(begin(v), end(v), s);
    std::cout << s; // Will print "Hello, Cruel World!"
}

或者，您可以使用更有效的小 for cycle：

Alternatively, you could use a more efficient, small for cycle:

#include <vector>
#include <string>
#include <iostream>

int main()
{
    std::vector<std::string> v{"Hello, ", "Cruel ", "World!"};
    std::string result;
    for (auto const& s : v) { result += s; }
    std::cout << s; // Will print "Hello, Cruel World!"
}

这篇关于如何从std :: vector中创建std :: string< string&gt ;?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！