std::flat_multiset<Key,Compare,KeyContainer>::erase

 

C++

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Named requirements

Feature test macros (C++20)

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Concepts library (C++20)

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Strings library

Containers library

Iterators library

Ranges library (C++20)

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Filesystem library (C++17)

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Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

mdspan (C++23)

Tables

Iterator invalidation

Member function table

Non-member function table

 

std::flat_multiset

Member types

Member functions

flat_multiset::flat_multiset   flat_multiset::operator= Iterators flat_multiset::beginflat_multiset::cbegin flat_multiset::endflat_multiset::cend flat_multiset::rbeginflat_multiset::crbegin flat_multiset::rendflat_multiset::crend Capacity flat_multiset::size flat_multiset::max_size flat_multiset::empty Observers flat_multiset::key_comp flat_multiset::value_comp Modifiers flat_multiset::clear flat_multiset::insert flat_multiset::insert_range flat_multiset::emplace flat_multiset::emplace_hint flat_multiset::erase flat_multiset::swap flat_multiset::extract flat_multiset::replace Lookup flat_multiset::count flat_multiset::find flat_multiset::contains flat_multiset::equal_range flat_multiset::lower_bound flat_multiset::upper_bound

Non-member functions

swap(std::flat_multiset) erase_if(std::flat_multiset)    operator==operator<=>

Helper classes

uses_allocator<std::flat_multiset>

Tags

sorted_equivalent         sorted_equivalent_t

Deduction guides

 

iterator erase( iterator position );	(1)	(since C++23)
iterator erase( const_iterator pos );	(2)	(since C++23)
iterator erase( const_iterator first, const_iterator last );	(3)	(since C++23)
size_type erase( const Key& key );	(4)	(since C++23)
template< class K > size_type erase( K&& x );	(5)	(since C++23)

Removes specified elements from the container. The order of the remaining equivalent elements is preserved.

1,2) Removes the element at pos.

3) Removes the elements in the range [first, last), which must be a valid range in *this.

4) Removes all elements with the key equivalent to key.

5) Removes all elements with key that compares equivalent to the value x. This overload participates in overload resolution only if the qualified-id Compare::is_transparent is valid and denotes a type, and neither iterator nor const_iterator is implicitly convertible from K. It allows calling this function without constructing an instance of Key.

The iterator pos must be valid and dereferenceable. Thus the end() iterator (which is valid, but is not dereferenceable) cannot be used as a value for pos.

Parameters

pos	-	iterator to the element to remove
first, last	-	range of elements to remove
key	-	key value of the elements to remove
x	-	a value of any type that can be transparently compared with a key denoting the elements to remove

Return value

1-3) Iterator following the last removed element.

4) Number of elements removed.

5) Number of elements removed.

Exceptions

1-3) Throws nothing.

4,5) Any exceptions thrown by the Compare object.

Complexity

Depends on underlying container. Typically linear.

Example

Run this code

#include <flat_set>
#include <iostream>
 
int main()
{
    std::flat_multiset<int> c = {1, 2, 3, 4, 1, 2, 3, 4};
 
    auto print = [&c]
    {
        std::cout << "c = { ";
        for (int n : c)
            std::cout << n << ' ';
        std::cout << "}\n";
    };
    print();
 
    std::cout << "Erase all odd numbers:\n";
    for (auto it = c.begin(); it != c.end();)
    {
        if (*it % 2 != 0)
            it = c.erase(it);
        else
            ++it;
    }
    print();
 
    std::cout << "Erase 1, erased count: " << c.erase(1) << '\n';
    std::cout << "Erase 2, erased count: " << c.erase(2) << '\n';
    std::cout << "Erase 2, erased count: " << c.erase(2) << '\n';
    print();
}

See also

clear

clears the contents (public member function)