inline constexpr auto values = ranges::elements<1>;
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.
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 <iostream>
#include <map>
#include <ranges>
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.
DR Applied to Behavior as published Correct behavior LWG 3563 C++20keys_view is unable to participate in CTAD due to its use of views::all_t views::all_t removed [edit] See also
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