How can you concisely combine a container of std::string_view
s?
For instance, boost::algorithm::join
is great, but it only works for std::string
.
An ideal implementation would be
static std::string_view unwords(const std::vector<std::string_view>& svVec) {
std::string_view joined;
boost::algorithm::join(svVec," ");
return joined;
}
short C++20 answer version:
using namespace std::literals;
const auto bits = { "https:"sv, "//"sv, "cppreference"sv, "."sv, "com"sv };
for (char const c : bits | std::views::join) std::cout << c;
std::cout << '\n';
since C++23 if you want to add special string or character between parts you can just use simple join_with and your code is just below (from official cppreference example)
#include <iostream>
#include <ranges>
#include <vector>
#include <string_view>
int main() {
using namespace std::literals;
std::vector v{"This"sv, "is"sv, "a"sv, "test."sv};
auto joined = v | std::views::join_with(' ');
for (auto c : joined) std::cout << c;
std::cout << '\n';
}
Note1: if you do not like use not stable release of language, you can simple use range-v3 library for join_with
views
Note2: As Nicol Bolas you cannot join literally to exact one string_view
without any copy (you can copy to string and ... :D), if you want to know more detailed about that you can see Why can't I construct a string_view from range iterators? SO question and answer.