std::ranges::views::values, std::ranges::values_view - cppreference.com (original) (raw)

Takes a view of tuple-like values (e.g. std::tuple or std::pair), and produces a view with a value-type of the second element of the adapted view's value-type.

[edit] Notes

values_view can be useful for extracting values from associative containers, e.g.

std::map<int, std::string> map{{1, "alpha"}, {2, "beta"}}; for (auto const& value : std::views::values(map)) std::cout << value << ' '; // prints: alpha beta

[edit] Example

#include #include #include   int main() { const auto list = {std::pair{1, 11.1}, {2, 22.2}, {3, 33.3}}; std::cout << "pair::second values in the list: "; for (double value : list | std::views::values) std::cout << value << ' ';   std::map<char, int> map{{'A', 1}, {'B', 2}, {'C', 3}, {'D', 4}, {'E', 5}}; auto odd = [](int x) { return 0 != (x & 1); }; std::cout << "\nodd values in the map: "; for (int value : map | std::views::values | std::views::filter(odd)) std::cout << value << ' '; std::cout << '\n'; }

Output:

pair::second values in the list: 11.1 22.2 33.3 odd values in the map: 1 3 5

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit] See also