std::flat_map<Key,T,Compare,KeyContainer,MappedContainer>::extract - cppreference.com (original) (raw)

| containers extract() &&; | | (since C++23) | | ------------------------ | | ------------- |

Extracts adapted containers c. Equivalent to return std::move(c);.

After this operation *this is empty, even if an exception is thrown.

[edit] Return value

std::move(c).

[edit] Complexity

Constant.

[edit] Example

#include #include #include #include #include #include   int main() { std::flat_map<int, double> map{{1, 1.1}, {2, 2.2}, {3, 3.3}}; const auto size{map.size()};   auto c{std::move(map).extract()}; assert(c.keys.size() == size); assert(c.values.size() == size); assert(map.empty()); assert(map.keys().empty()); assert(map.values().empty());   // The default keys and values containers are std::vector: static_assert(std::is_same_v<decltype(c.keys), std::vector>); static_assert(std::is_same_v<decltype(c.values), std::vector>);   std::println("keys: {}", c.keys); std::println("values: {}", c.values); }

Output:

keys: [1, 2, 3] values: [1.1, 2.2, 3.3]

[edit] See also

| | replaces the underlying containers (public member function) [edit] | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |