C++ 将 vector<int> 转换为字符串
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Converting a vector<int> to string
提问by shn
In C++, what is the simplest way to convert a vector of ints (i.e. vector<int>) to a string ?
在 C++ 中，将整数向量（即vector<int>）转换为字符串的最简单方法是什么？
回答by Drew Chapin
I usually do it this way...
我一般都是这样的...
#include <string>
#include <vector>
int main( int argc, char* argv[] )
{
std::vector<char> vec;
//... do something with vec
std::string str(vec.begin(), vec.end());
//... do something with str
return 0;
}
回答by Fred Larson
Maybe std::ostream_iteratorand std::ostringstream:
也许std::ostream_iterator和std::ostringstream：
#include <vector>
#include <string>
#include <algorithm>
#include <sstream>
#include <iterator>
#include <iostream>
int main()
{
std::vector<int> vec;
vec.push_back(1);
vec.push_back(4);
vec.push_back(7);
vec.push_back(4);
vec.push_back(9);
vec.push_back(7);
std::ostringstream oss;
if (!vec.empty())
{
// Convert all but the last element to avoid a trailing ","
std::copy(vec.begin(), vec.end()-1,
std::ostream_iterator<int>(oss, ","));
// Now add the last element with no delimiter
oss << vec.back();
}
std::cout << oss.str() << std::endl;
}
回答by Rob?
Here is an alternative which uses a custom output iterator. This example behaves correctly for the case of an empty list. This example demonstrates how to create a custom output iterator, similar to std::ostream_iterator.
这是使用自定义输出迭代器的替代方法。对于空列表的情况，此示例的行为正确。此示例演示如何创建自定义输出迭代器，类似于std::ostream_iterator.
#include <iterator>
#include <vector>
#include <iostream>
#include <sstream>
struct CommaIterator
:
public std::iterator<std::output_iterator_tag, void, void, void, void>
{
std::ostream *os;
std::string comma;
bool first;
CommaIterator(std::ostream& os, const std::string& comma)
:
os(&os), comma(comma), first(true)
{
}
CommaIterator& operator++() { return *this; }
CommaIterator& operator++(int) { return *this; }
CommaIterator& operator*() { return *this; }
template <class T>
CommaIterator& operator=(const T& t) {
if(first)
first = false;
else
*os << comma;
*os << t;
return *this;
}
};
int main () {
// The vector to convert
std::vector<int> v(3,3);
// Convert vector to string
std::ostringstream oss;
std::copy(v.begin(), v.end(), CommaIterator(oss, ","));
std::string result = oss.str();
const char *c_result = result.c_str();
// Display the result;
std::cout << c_result << "\n";
}
回答by kpgbrink
template<typename T>
string str(T begin, T end)
{
stringstream ss;
bool first = true;
for (; begin != end; begin++)
{
if (!first)
ss << ", ";
ss << *begin;
first = false;
}
return ss.str();
}
This is the str function that can make integers turn into a string and not into a char for what the integer represents. Also works for doubles.
这是 str 函数，它可以使整数变成字符串，而不是整数所代表的字符。也适用于双打。
