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Member function table | ||||
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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 rangerg if and only if there is no element with key equivalent to the key of that element in*this.
Each iterator in the rangerg is dereferenced exactly once.
If any of the following conditions is satisfied, the behavior is undefined:
value_type
is notEmplaceConstructible intounordered_map
from*ranges::begin(rg)If after the operation the new number of elements is greater than oldmax_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.
Contents |
rg | - | acontainer compatible range, that is, aninput_range whose elements are convertible toT |
Average case\(\scriptsize N\)N, worst case\(\scriptsize O(N \cdot S + N)\)O(N·S+N), where\(\scriptsize S\)S issize() and\(\scriptsize N\)N isranges::distance(rg).
Feature-test macro | Value | Std | Feature |
---|---|---|---|
__cpp_lib_containers_ranges | 202202L | (C++23) | Ranges-aware construction and insertion |
#include <iostream>#include <unordered_map>#include <utility> void println(auto,constauto& container){for(constauto&[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}};constauto 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}
inserts elementsor nodes(since C++17) (public member function)[edit] |