std::vector::assign_range(3)

💖 std::vector::assign_range(3) 💖

okay so we're opening the std::vector::assign_range(3) page from the C++ Standard Libary manual, and honestly? this one is giving “replace the whole container’s vibe with a range” energy. let’s go ✨

✨ NAME ✨

std::vector::assign_range - std::vector::assign_range

🦋 Synopsis 🦋

template< container-compatible-range<T> R >  (since C++23)
constexpr void assign_range( R&& rg );

🌸 Description 🌸

So what it does is: it replaces the elements in the container with a copy of each element in rg. cute, simple, effective 💅

All iterators — including the end() iterator — and references to the elements are invalidated. no cap, they’re gone.

Each iterator in the range rg is dereferenced exactly once. one and done, bestie.

⚠️ The behavior is undefined if rg overlaps with the container. like, do not do that. fr fr 😭

🎀 Parameters 🎀

• rg — an input_range with reference type convertible to the element type of the container.

🧚 Type requirements 🧚

• std::assignable_from<T&, ranges::range_reference_t<R>> must be modeled. Otherwise, the program is ill-formed.
• T must be EmplaceConstructible into the container from *ranges::begin(rg). If R models neither sized_range nor forward_range, T must be also MoveInsertable into the container. Otherwise, the behavior is undefined.

💖 Return value 💖

(none) — literally nothing, bestie. it just does the thing 🫶

🔥 Notes 🔥

Feature-test macro vibes:

• Feature-test macro: __cpp_lib_containers_ranges
• Value: 202202L
• Std: (C++23)
• Feature: Ranges-aware construction and insertion

🌈 Example 🌈

Run this code:

#include <algorithm>
#include <cassert>
#include <vector>
#include <list>

int main()
{
    const auto source = std::list{2, 7, 1};
    auto destination = std::vector{3, 1, 4};
#ifdef __cpp_lib_containers_ranges
    destination.assign_range(source);
#else
    destination.assign(source.cbegin(), source.cend());
#endif
    assert(std::ranges::equal(source, destination));
}

👑 See also 👑

• insert_range — inserts a range of elements (C++23) (public member function)
• append_range — adds a range of elements to the end (C++23) (public member function)
• assign — assigns values to the container (public member function)

---

mwah 💋 this page came from http://cppreference.com, dated 2024.06.10, and it is literally std::vector::assign_range(3). bye bestie, go assign some ranges responsibly 🫶✨