map-usage.cpp

#include <ext/map.hpp>
#include <vector>
#include <iostream>

int main() {
	const std::vector<std::pair<std::string, std::string>> collection{
		{ "first", "primero" },
		{ "second", "segundo" },
		{ "third", "tercero" }
	};

	const auto print = [] (const auto & collection) {
		std::copy(std::begin(collection), std::end(collection), std::ostream_iterator<std::string>{std::cout, " "});
		std::cout << std::endl;
	};

	/// specifying result collection template is not really necessary, type-deduction will do
	const auto en = ext::map<std::vector>(collection, [] (auto & collection) {
		return collection.first;
	});
	print(en);

	const auto es = ext::map<std::vector>(collection, [] (auto & collection) {
		return collection.second;
	});
	print(es);
}