std::unordered_map::equal_range

 

C++

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std::unordered_map

Member functions

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::erase

unordered_map::size

unordered_map::max_size

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unordered_map::clear

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unordered_map::swap

Lookup

unordered_map::count

unordered_map::find

unordered_map::equal_range

Bucket interface

unordered_map::begin2

unordered_map::end2

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

 

std::pair<iterator,iterator> equal_range( const Key& key );		(since C++11)
std::pair<const_iterator,const_iterator> equal_range( const Key& key ) const;		(since C++11)

Returns a range containing all elements with key key in the container. The range is defined by two iterators, the first pointing to the first element of the wanted range and the second pointing past the last element of the range.

Parameters

key

-

key value to compare the elements to

Return value

std::pair containing a pair of iterators defining the wanted range. If there are no such elements, past-the-end (see end()) iterators are returned as both elements of the pair.

Complexity

Average case constant, worst case linear in the size of the container.

Example

Run this code

#include <iostream>
#include <unordered_map>
 
int main()
{  
    std::unordered_map<int,char> map = {{1,'a'},{1,'b'},{1,'d'},{2,'b'}};
    auto range = map.equal_range(1);
    for (auto it = range.first; it != range.second; ++it) {
        std::cout << it->first << ' ' << it->second << '\n';
    }
}

Output:

1 a

See also

find	finds element with specific key (public member function)