std::unordered_map<Key,T,Hash,KeyEqual,Allocator>::insert_range

 

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std::unordered_map

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unordered_map::unordered_map unordered_map::~unordered_map unordered_map::operator= unordered_map::get_allocator Iterators unordered_map::beginunordered_map::cbegin unordered_map::endunordered_map::cend Capacity unordered_map::size unordered_map::max_size unordered_map::empty Modifiers unordered_map::clear unordered_map::erase unordered_map::swap unordered_map::extract (C++17) unordered_map::merge (C++17) unordered_map::insert unordered_map::insert_range (C++23) unordered_map::insert_or_assign (C++17)   unordered_map::emplace unordered_map::emplace_hint unordered_map::try_emplace (C++17)	Lookup unordered_map::at unordered_map::operator[] unordered_map::count unordered_map::find unordered_map::contains (C++20) unordered_map::equal_range Bucket interface unordered_map::begin(size_type)unordered_map::cbegin(size_type) unordered_map::end(size_type)unordered_map::cend(size_type) unordered_map::bucket_count unordered_map::max_bucket_count unordered_map::bucket_size unordered_map::bucket Hash policy unordered_map::load_factor unordered_map::max_load_factor unordered_map::rehash unordered_map::reserve Observers unordered_map::hash_function unordered_map::key_eq
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operator==operator!= (until C++20)	std::swap(std::unordered_map) erase_if(std::unordered_map) (C++20)
Deduction guides(C++17)

 

template< container-compatible-range<value_type> R > void insert_range( R&& rg );		(since C++23) (constexpr since C++26)

Inserts a copy of each element in the range rg if and only if there is no element with key equivalent to the key of that element in *this.

Each iterator in the range rg is dereferenced exactly once.

If any of the following conditions is satisfied, the behavior is undefined:

• value_type is not EmplaceConstructible into unordered_map from *ranges::begin(rg)
• rg and *this overlap.

If after the operation the new number of elements is greater than old max_load_factor() * bucket_count() a rehashing takes place.
If rehashing occurs (due to the insertion), all iterators are invalidated. Otherwise (no rehashing), iterators are not invalidated.

Parameters

rg

-

a container compatible range, that is, an input_range whose elements are convertible to T

Complexity

Average case \(\scriptsize N\)N, worst case \(\scriptsize O(N \cdot S + N)\)O(N·S+N), where \(\scriptsize S\)S is size() and \(\scriptsize N\)N is ranges::distance(rg).

Notes

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

Example

Run this code

#include <iostream>
#include <unordered_map>
#include <utility>
 
void println(auto, const auto& container)
{
    for (const auto& [key, value] : container)
        std::cout << '{' << key << ',' << value << '}' << ' ';
    std::cout << '\n';
}
 
int main()
{
    auto container = std::unordered_map{std::pair{1, 11}, {3, 33}, {2, 22}, {4, 44};
    const auto rg = {std::pair{-1, -11}, {3, -33}, {-2, -22};
#ifdef __cpp_lib_containers_ranges
    container.insert_range(rg);
#else
    container.insert(rg.begin(), rg.end();
#endif
    println("{}", container);
}

Possible output:

{4,44} {-1,-11} {2,22} {3,33} {-2,-22} {1,11}

See also

insert

inserts elements or nodes(since C++17) (public member function)

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