std::ranges::views::elements, std::ranges::elements_view

elements_view models the concepts random_access_range, bidirectional_range, forward_range, input_range, common_range, and sized_range when the underlying view V models respective concepts.

Expression-equivalent

Expression e is expression-equivalent to expression f, if e and f have the same effects, either are both potentially-throwing or are both not potentially-throwing (i.e. noexcept(e) == noexcept(f)), and either are both constant subexpressions or are both not constant subexpressions.

Member functions

Nested classes

Helper templates

This specialization of std::ranges::enable_borrowed_range makes elements_view satisfy borrowed_range when the underlying view satisfies it.

Example

#include <iostream>
#include <ranges>
#include <tuple>
#include <vector>
 
int main()
{
    const std::vector<std::tuple<int, char, std::string>> vt {
        {1, 'A', "α"},
        {2, 'B', "β"},
        {3, 'C', "γ"},
        {4, 'D', "δ"},
        {5, 'E', "ε"},
    };
 
    for (int const e: std::views::elements<0>(vt)) { std::cout << e << ' '; }
    std::cout << '\n';
    for (char const e: vt | std::views::elements<1>) { std::cout << e << ' '; }
    std::cout << '\n';
    for (std::string const& e: std::views::elements<2>(vt)) { std::cout << e << ' '; }
    std::cout << '\n';
}

1 2 3 4 5 
A B C D E 
α β γ δ ε

Defect reports

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

See also