libstdc++
std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc > Class Template Reference

Public Types

using insert_return_type = typename _Hashtable::insert_return_type
 
using node_type = typename _Hashtable::node_type
 
typedef _Hashtable::key_type key_type
 
typedef _Hashtable::value_type value_type
 
typedef _Hashtable::mapped_type mapped_type
 
typedef _Hashtable::hasher hasher
 
typedef _Hashtable::key_equal key_equal
 
typedef _Hashtable::allocator_type allocator_type
 
typedef _Hashtable::pointer pointer
 
typedef _Hashtable::const_pointer const_pointer
 
typedef _Hashtable::reference reference
 
typedef _Hashtable::const_reference const_reference
 
typedef _Hashtable::iterator iterator
 
typedef _Hashtable::const_iterator const_iterator
 
typedef _Hashtable::local_iterator local_iterator
 
typedef _Hashtable::const_local_iterator const_local_iterator
 
typedef _Hashtable::size_type size_type
 
typedef _Hashtable::difference_type difference_type
 

Public Member Functions

 unordered_map ()=default
 
template<typename _InputIterator >
 unordered_map (_InputIterator __first, _InputIterator __last, size_type __n, const allocator_type &__a)
 
template<typename _InputIterator >
 unordered_map (_InputIterator __first, _InputIterator __last, size_type __n, const hasher &__hf, const allocator_type &__a)
 
template<typename _InputIterator >
 unordered_map (_InputIterator __first, _InputIterator __last, size_type __n=0, const hasher &__hf=hasher(), const key_equal &__eql=key_equal(), const allocator_type &__a=allocator_type())
 
 unordered_map (const allocator_type &__a)
 
 unordered_map (const unordered_map &)=default
 
 unordered_map (const unordered_map &__umap, const allocator_type &__a)
 
 unordered_map (initializer_list< value_type > __l, size_type __n, const allocator_type &__a)
 
 unordered_map (initializer_list< value_type > __l, size_type __n, const hasher &__hf, const allocator_type &__a)
 
 unordered_map (initializer_list< value_type > __l, size_type __n=0, const hasher &__hf=hasher(), const key_equal &__eql=key_equal(), const allocator_type &__a=allocator_type())
 
 unordered_map (size_type __n, const allocator_type &__a)
 
 unordered_map (size_type __n, const hasher &__hf, const allocator_type &__a)
 
 unordered_map (size_type __n, const hasher &__hf=hasher(), const key_equal &__eql=key_equal(), const allocator_type &__a=allocator_type())
 
 unordered_map (unordered_map &&)=default
 
 unordered_map (unordered_map &&__umap, const allocator_type &__a) noexcept(noexcept(_Hashtable(std::move(__umap._M_h), __a)))
 
iterator begin () noexcept
 
local_iterator begin (size_type __n)
 
size_type bucket (const key_type &__key) const
 
size_type bucket_count () const noexcept
 
size_type bucket_size (size_type __n) const
 
void clear () noexcept
 
template<typename... _Args>
std::pair< iterator, bool > emplace (_Args &&... __args)
 
template<typename... _Args>
iterator emplace_hint (const_iterator __pos, _Args &&... __args)
 
bool empty () const noexcept
 
iterator end () noexcept
 
local_iterator end (size_type __n)
 
size_type erase (const key_type &__x)
 
iterator erase (const_iterator __first, const_iterator __last)
 
node_type extract (const key_type &__key)
 
node_type extract (const_iterator __pos)
 
allocator_type get_allocator () const noexcept
 
hasher hash_function () const
 
template<typename _InputIterator >
void insert (_InputIterator __first, _InputIterator __last)
 
iterator insert (const_iterator, node_type &&__nh)
 
void insert (initializer_list< value_type > __l)
 
insert_return_type insert (node_type &&__nh)
 
template<typename _Obj >
pair< iterator, bool > insert_or_assign (const key_type &__k, _Obj &&__obj)
 
template<typename _Obj >
iterator insert_or_assign (const_iterator __hint, const key_type &__k, _Obj &&__obj)
 
template<typename _Obj >
iterator insert_or_assign (const_iterator __hint, key_type &&__k, _Obj &&__obj)
 
template<typename _Obj >
pair< iterator, bool > insert_or_assign (key_type &&__k, _Obj &&__obj)
 
key_equal key_eq () const
 
float load_factor () const noexcept
 
size_type max_bucket_count () const noexcept
 
float max_load_factor () const noexcept
 
void max_load_factor (float __z)
 
size_type max_size () const noexcept
 
template<typename _H2 , typename _P2 >
void merge (unordered_map< _Key, _Tp, _H2, _P2, _Alloc > &&__source)
 
template<typename _H2 , typename _P2 >
void merge (unordered_map< _Key, _Tp, _H2, _P2, _Alloc > &__source)
 
template<typename _H2 , typename _P2 >
void merge (unordered_multimap< _Key, _Tp, _H2, _P2, _Alloc > &&__source)
 
template<typename _H2 , typename _P2 >
void merge (unordered_multimap< _Key, _Tp, _H2, _P2, _Alloc > &__source)
 
unordered_mapoperator= (const unordered_map &)=default
 
unordered_mapoperator= (initializer_list< value_type > __l)
 
unordered_mapoperator= (unordered_map &&)=default
 
void rehash (size_type __n)
 
void reserve (size_type __n)
 
size_type size () const noexcept
 
void swap (unordered_map &__x) noexcept(noexcept(_M_h.swap(__x._M_h)))
 
template<typename... _Args>
pair< iterator, bool > try_emplace (const key_type &__k, _Args &&... __args)
 
template<typename... _Args>
iterator try_emplace (const_iterator __hint, const key_type &__k, _Args &&... __args)
 
template<typename... _Args>
iterator try_emplace (const_iterator __hint, key_type &&__k, _Args &&... __args)
 
template<typename... _Args>
pair< iterator, bool > try_emplace (key_type &&__k, _Args &&... __args)
 
const_iterator begin () const noexcept
 
const_iterator cbegin () const noexcept
 
const_iterator end () const noexcept
 
const_iterator cend () const noexcept
 
std::pair< iterator, bool > insert (const value_type &__x)
 
std::pair< iterator, bool > insert (value_type &&__x)
 
template<typename _Pair >
__enable_if_t< is_constructible< value_type, _Pair && >::value, pair< iterator, bool > > insert (_Pair &&__x)
 
iterator insert (const_iterator __hint, const value_type &__x)
 
iterator insert (const_iterator __hint, value_type &&__x)
 
template<typename _Pair >
__enable_if_t< is_constructible< value_type, _Pair && >::value, iteratorinsert (const_iterator __hint, _Pair &&__x)
 
iterator erase (const_iterator __position)
 
iterator erase (iterator __position)
 
iterator find (const key_type &__x)
 
const_iterator find (const key_type &__x) const
 
size_type count (const key_type &__x) const
 
std::pair< iterator, iteratorequal_range (const key_type &__x)
 
std::pair< const_iterator, const_iteratorequal_range (const key_type &__x) const
 
mapped_typeoperator[] (const key_type &__k)
 
mapped_typeoperator[] (key_type &&__k)
 
mapped_typeat (const key_type &__k)
 
const mapped_typeat (const key_type &__k) const
 
const_local_iterator begin (size_type __n) const
 
const_local_iterator cbegin (size_type __n) const
 
const_local_iterator end (size_type __n) const
 
const_local_iterator cend (size_type __n) const
 

Friends

template<typename _Key1 , typename _Tp1 , typename _Hash1 , typename _Pred1 , typename _Alloc1 >
bool operator== (const unordered_map< _Key1, _Tp1, _Hash1, _Pred1, _Alloc1 > &, const unordered_map< _Key1, _Tp1, _Hash1, _Pred1, _Alloc1 > &)
 
template<typename , typename , typename >
class std::_Hash_merge_helper
 

Detailed Description

template<typename _Key, typename _Tp, typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
class std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >

A standard container composed of unique keys (containing at most one of each key value) that associates values of another type with the keys.

Template Parameters
_KeyType of key objects.
_TpType of mapped objects.
_HashHashing function object type, defaults to hash<_Value>.
_PredPredicate function object type, defaults to equal_to<_Value>.
_AllocAllocator type, defaults to std::allocator<std::pair<const _Key, _Tp>>.

Meets the requirements of a container, and unordered associative container

The resulting value type of the container is std::pair<const _Key, _Tp>.

Base is _Hashtable, dispatched at compile time via template alias __umap_hashtable.

Definition at line 102 of file unordered_map.h.

Member Typedef Documentation

◆ allocator_type

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::allocator_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::allocator_type

Public typedefs.

Definition at line 116 of file unordered_map.h.

◆ const_iterator

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::const_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::const_iterator

Iterator-related typedefs.

Definition at line 126 of file unordered_map.h.

◆ const_local_iterator

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::const_local_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::const_local_iterator

Iterator-related typedefs.

Definition at line 128 of file unordered_map.h.

◆ const_pointer

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::const_pointer std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::const_pointer

Iterator-related typedefs.

Definition at line 122 of file unordered_map.h.

◆ const_reference

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::const_reference std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::const_reference

Iterator-related typedefs.

Definition at line 124 of file unordered_map.h.

◆ difference_type

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::difference_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::difference_type

Iterator-related typedefs.

Definition at line 130 of file unordered_map.h.

◆ hasher

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::hasher std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::hasher

Public typedefs.

Definition at line 114 of file unordered_map.h.

◆ iterator

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::iterator

Iterator-related typedefs.

Definition at line 125 of file unordered_map.h.

◆ key_equal

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::key_equal std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::key_equal

Public typedefs.

Definition at line 115 of file unordered_map.h.

◆ key_type

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::key_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::key_type

Public typedefs.

Definition at line 111 of file unordered_map.h.

◆ local_iterator

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::local_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::local_iterator

Iterator-related typedefs.

Definition at line 127 of file unordered_map.h.

◆ mapped_type

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::mapped_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::mapped_type

Public typedefs.

Definition at line 113 of file unordered_map.h.

◆ pointer

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::pointer std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::pointer

Iterator-related typedefs.

Definition at line 121 of file unordered_map.h.

◆ reference

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::reference std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::reference

Iterator-related typedefs.

Definition at line 123 of file unordered_map.h.

◆ size_type

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::size_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::size_type

Iterator-related typedefs.

Definition at line 129 of file unordered_map.h.

◆ value_type

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
typedef _Hashtable::value_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::value_type

Public typedefs.

Definition at line 112 of file unordered_map.h.

Constructor & Destructor Documentation

◆ unordered_map() [1/7]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::unordered_map ( )
default

Default constructor.

◆ unordered_map() [2/7]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::unordered_map ( size_type  __n,
const hasher __hf = hasher(),
const key_equal __eql = key_equal(),
const allocator_type __a = allocator_type() 
)
inlineexplicit

Default constructor creates no elements.

Parameters
__nMinimal initial number of buckets.
__hfA hash functor.
__eqlA key equality functor.
__aAn allocator object.

Definition at line 151 of file unordered_map.h.

◆ unordered_map() [3/7]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename _InputIterator >
std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::unordered_map ( _InputIterator  __first,
_InputIterator  __last,
size_type  __n = 0,
const hasher __hf = hasher(),
const key_equal __eql = key_equal(),
const allocator_type __a = allocator_type() 
)
inline

Builds an unordered_map from a range.

Parameters
__firstAn input iterator.
__lastAn input iterator.
__nMinimal initial number of buckets.
__hfA hash functor.
__eqlA key equality functor.
__aAn allocator object.

Create an unordered_map consisting of copies of the elements from [__first,__last). This is linear in N (where N is distance(__first,__last)).

Definition at line 172 of file unordered_map.h.

◆ unordered_map() [4/7]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::unordered_map ( const unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc > &  )
default

Copy constructor.

◆ unordered_map() [5/7]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::unordered_map ( unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc > &&  )
default

Move constructor.

◆ unordered_map() [6/7]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::unordered_map ( const allocator_type __a)
inlineexplicit

Creates an unordered_map with no elements.

Parameters
__aAn allocator object.

Definition at line 191 of file unordered_map.h.

◆ unordered_map() [7/7]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::unordered_map ( initializer_list< value_type __l,
size_type  __n = 0,
const hasher __hf = hasher(),
const key_equal __eql = key_equal(),
const allocator_type __a = allocator_type() 
)
inline

Builds an unordered_map from an initializer_list.

Parameters
__lAn initializer_list.
__nMinimal initial number of buckets.
__hfA hash functor.
__eqlA key equality functor.
__aAn allocator object.

Create an unordered_map consisting of copies of the elements in the list. This is linear in N (where N is __l.size()).

Definition at line 227 of file unordered_map.h.

Member Function Documentation

◆ at() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
mapped_type& std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::at ( const key_type __k)
inline

Access to unordered_map data.

Parameters
__kThe key for which data should be retrieved.
Returns
A reference to the data whose key is equal to __k, if such a data is present in the unordered_map.
Exceptions
std::out_of_rangeIf no such data is present.

Definition at line 996 of file unordered_map.h.

◆ at() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const mapped_type& std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::at ( const key_type __k) const
inline

Access to unordered_map data.

Parameters
__kThe key for which data should be retrieved.
Returns
A reference to the data whose key is equal to __k, if such a data is present in the unordered_map.
Exceptions
std::out_of_rangeIf no such data is present.

Definition at line 1000 of file unordered_map.h.

◆ begin() [1/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::begin ( ) const
inlinenoexcept

Returns a read-only (constant) iterator that points to the first element in the unordered_map.

Definition at line 334 of file unordered_map.h.

◆ begin() [2/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::begin ( )
inlinenoexcept

Returns a read/write iterator that points to the first element in the unordered_map.

Definition at line 325 of file unordered_map.h.

◆ begin() [3/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
local_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::begin ( size_type  __n)
inline

Returns a read/write iterator pointing to the first bucket element.

Parameters
__nThe bucket index.
Returns
A read/write local iterator.

Definition at line 1041 of file unordered_map.h.

◆ begin() [4/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const_local_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::begin ( size_type  __n) const
inline

Returns a read-only (constant) iterator pointing to the first bucket element.

Parameters
__nThe bucket index.
Returns
A read-only local iterator.

Definition at line 1052 of file unordered_map.h.

◆ bucket_count()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
size_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::bucket_count ( ) const
inlinenoexcept

Returns the number of buckets of the unordered_map.

Definition at line 1008 of file unordered_map.h.

◆ cbegin() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::cbegin ( ) const
inlinenoexcept

Returns a read-only (constant) iterator that points to the first element in the unordered_map.

Definition at line 338 of file unordered_map.h.

◆ cbegin() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const_local_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::cbegin ( size_type  __n) const
inline

Returns a read-only (constant) iterator pointing to the first bucket element.

Parameters
__nThe bucket index.
Returns
A read-only local iterator.

Definition at line 1056 of file unordered_map.h.

◆ cend() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::cend ( ) const
inlinenoexcept

Returns a read-only (constant) iterator that points one past the last element in the unordered_map.

Definition at line 360 of file unordered_map.h.

Referenced by std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert_or_assign(), and std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::try_emplace().

◆ cend() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const_local_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::cend ( size_type  __n) const
inline

Returns a read-only (constant) iterator pointing to one past the last bucket elements.

Parameters
__nThe bucket index.
Returns
A read-only local iterator.

Definition at line 1082 of file unordered_map.h.

◆ clear()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
void std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::clear ( )
inlinenoexcept

Erases all elements in an unordered_map. Note that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Definition at line 790 of file unordered_map.h.

◆ count()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
size_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::count ( const key_type __x) const
inline

Finds the number of elements.

Parameters
__xKey to count.
Returns
Number of elements with specified key.

This function only makes sense for unordered_multimap; for unordered_map the result will either be 0 (not present) or 1 (present).

Definition at line 901 of file unordered_map.h.

◆ emplace()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename... _Args>
std::pair<iterator, bool> std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::emplace ( _Args &&...  __args)
inline

Attempts to build and insert a std::pair into the unordered_map.

Parameters
__argsArguments used to generate a new pair instance (see std::piecewise_contruct for passing arguments to each part of the pair constructor).
Returns
A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to build and insert a (key, value) pair into the unordered_map. An unordered_map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the unordered_map.

Insertion requires amortized constant time.

Definition at line 388 of file unordered_map.h.

◆ emplace_hint()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename... _Args>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::emplace_hint ( const_iterator  __pos,
_Args &&...  __args 
)
inline

Attempts to build and insert a std::pair into the unordered_map.

Parameters
__posAn iterator that serves as a hint as to where the pair should be inserted.
__argsArguments used to generate a new pair instance (see std::piecewise_contruct for passing arguments to each part of the pair constructor).
Returns
An iterator that points to the element with key of the std::pair built from __args (may or may not be that std::pair).

This function is not concerned about whether the insertion took place, and thus does not return a boolean like the single-argument emplace() does. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints for more on hinting.

Insertion requires amortized constant time.

Definition at line 419 of file unordered_map.h.

◆ empty()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
bool std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::empty ( ) const
inlinenoexcept

Returns true if the unordered_map is empty.

Definition at line 305 of file unordered_map.h.

◆ end() [1/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::end ( ) const
inlinenoexcept

Returns a read-only (constant) iterator that points one past the last element in the unordered_map.

Definition at line 356 of file unordered_map.h.

◆ end() [2/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::end ( )
inlinenoexcept

Returns a read/write iterator that points one past the last element in the unordered_map.

Definition at line 347 of file unordered_map.h.

◆ end() [3/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
local_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::end ( size_type  __n)
inline

Returns a read/write iterator pointing to one past the last bucket elements.

Parameters
__nThe bucket index.
Returns
A read/write local iterator.

Definition at line 1067 of file unordered_map.h.

◆ end() [4/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const_local_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::end ( size_type  __n) const
inline

Returns a read-only (constant) iterator pointing to one past the last bucket elements.

Parameters
__nThe bucket index.
Returns
A read-only local iterator.

Definition at line 1078 of file unordered_map.h.

◆ equal_range() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::pair<iterator, iterator> std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::equal_range ( const key_type __x)
inline

Finds a subsequence matching given key.

Parameters
__xKey to be located.
Returns
Pair of iterators that possibly points to the subsequence matching given key.

This function probably only makes sense for unordered_multimap.

Definition at line 941 of file unordered_map.h.

◆ equal_range() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::pair<const_iterator, const_iterator> std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::equal_range ( const key_type __x) const
inline

Finds a subsequence matching given key.

Parameters
__xKey to be located.
Returns
Pair of iterators that possibly points to the subsequence matching given key.

This function probably only makes sense for unordered_multimap.

Definition at line 953 of file unordered_map.h.

◆ erase() [1/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
size_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::erase ( const key_type __x)
inline

Erases elements according to the provided key.

Parameters
__xKey of element to be erased.
Returns
The number of elements erased.

This function erases all the elements located by the given key from an unordered_map. For an unordered_map the result of this function can only be 0 (not present) or 1 (present). Note that this function only erases the element, and that if the element is itself a pointer, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Definition at line 762 of file unordered_map.h.

◆ erase() [2/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::erase ( const_iterator  __first,
const_iterator  __last 
)
inline

Erases a [__first,__last) range of elements from an unordered_map.

Parameters
__firstIterator pointing to the start of the range to be erased.
__lastIterator pointing to the end of the range to be erased.
Returns
The iterator __last.

This function erases a sequence of elements from an unordered_map. Note that this function only erases the elements, and that if the element is itself a pointer, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Definition at line 780 of file unordered_map.h.

◆ erase() [3/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::erase ( const_iterator  __position)
inline

Erases an element from an unordered_map.

Parameters
__positionAn iterator pointing to the element to be erased.
Returns
An iterator pointing to the element immediately following __position prior to the element being erased. If no such element exists, end() is returned.

This function erases an element, pointed to by the given iterator, from an unordered_map. Note that this function only erases the element, and that if the element is itself a pointer, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Definition at line 740 of file unordered_map.h.

◆ erase() [4/4]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::erase ( iterator  __position)
inline

Erases an element from an unordered_map.

Parameters
__positionAn iterator pointing to the element to be erased.
Returns
An iterator pointing to the element immediately following __position prior to the element being erased. If no such element exists, end() is returned.

This function erases an element, pointed to by the given iterator, from an unordered_map. Note that this function only erases the element, and that if the element is itself a pointer, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Definition at line 745 of file unordered_map.h.

◆ extract() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
node_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::extract ( const key_type __key)
inline

Extract a node.

Definition at line 433 of file unordered_map.h.

◆ extract() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
node_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::extract ( const_iterator  __pos)
inline

Extract a node.

Definition at line 425 of file unordered_map.h.

◆ find() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::find ( const key_type __x)
inline

Tries to locate an element in an unordered_map.

Parameters
__xKey to be located.
Returns
Iterator pointing to sought-after element, or end() if not found.

This function takes a key and tries to locate the element with which the key matches. If successful the function returns an iterator pointing to the sought after element. If unsuccessful it returns the past-the-end ( end() ) iterator.

Definition at line 868 of file unordered_map.h.

◆ find() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
const_iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::find ( const key_type __x) const
inline

Tries to locate an element in an unordered_map.

Parameters
__xKey to be located.
Returns
Iterator pointing to sought-after element, or end() if not found.

This function takes a key and tries to locate the element with which the key matches. If successful the function returns an iterator pointing to the sought after element. If unsuccessful it returns the past-the-end ( end() ) iterator.

Definition at line 879 of file unordered_map.h.

◆ get_allocator()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
allocator_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::get_allocator ( ) const
inlinenoexcept

Returns the allocator object used by the unordered_map.

Definition at line 298 of file unordered_map.h.

◆ hash_function()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
hasher std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::hash_function ( ) const
inline

Returns the hash functor object with which the unordered_map was constructed.

Definition at line 844 of file unordered_map.h.

◆ insert() [1/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename _InputIterator >
void std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( _InputIterator  __first,
_InputIterator  __last 
)
inline

A template function that attempts to insert a range of elements.

Parameters
__firstIterator pointing to the start of the range to be inserted.
__lastIterator pointing to the end of the range.

Complexity similar to that of the range constructor.

Definition at line 616 of file unordered_map.h.

◆ insert() [2/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename _Pair >
__enable_if_t<is_constructible<value_type, _Pair&&>::value, pair<iterator, bool> > std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( _Pair &&  __x)
inline

Attempts to insert a std::pair into the unordered_map.

Parameters
__xPair to be inserted (see std::make_pair for easy creation of pairs).
Returns
A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the unordered_map. An unordered_map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the unordered_map.

Insertion requires amortized constant time.

Definition at line 563 of file unordered_map.h.

◆ insert() [3/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::pair<iterator, bool> std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( const value_type __x)
inline

Attempts to insert a std::pair into the unordered_map.

Parameters
__xPair to be inserted (see std::make_pair for easy creation of pairs).
Returns
A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the unordered_map. An unordered_map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the unordered_map.

Insertion requires amortized constant time.

Definition at line 551 of file unordered_map.h.

◆ insert() [4/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename _Pair >
__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator> std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( const_iterator  __hint,
_Pair &&  __x 
)
inline

Attempts to insert a std::pair into the unordered_map.

Parameters
__hintAn iterator that serves as a hint as to where the pair should be inserted.
__xPair to be inserted (see std::make_pair for easy creation of pairs).
Returns
An iterator that points to the element with key of __x (may or may not be the pair passed in).

This function is not concerned about whether the insertion took place, and thus does not return a boolean like the single-argument insert() does. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints for more on hinting.

Insertion requires amortized constant time.

Definition at line 601 of file unordered_map.h.

◆ insert() [5/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( const_iterator  __hint,
const value_type __x 
)
inline

Attempts to insert a std::pair into the unordered_map.

Parameters
__hintAn iterator that serves as a hint as to where the pair should be inserted.
__xPair to be inserted (see std::make_pair for easy creation of pairs).
Returns
An iterator that points to the element with key of __x (may or may not be the pair passed in).

This function is not concerned about whether the insertion took place, and thus does not return a boolean like the single-argument insert() does. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints for more on hinting.

Insertion requires amortized constant time.

Definition at line 590 of file unordered_map.h.

◆ insert() [6/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( const_iterator  __hint,
value_type &&  __x 
)
inline

Attempts to insert a std::pair into the unordered_map.

Parameters
__hintAn iterator that serves as a hint as to where the pair should be inserted.
__xPair to be inserted (see std::make_pair for easy creation of pairs).
Returns
An iterator that points to the element with key of __x (may or may not be the pair passed in).

This function is not concerned about whether the insertion took place, and thus does not return a boolean like the single-argument insert() does. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints for more on hinting.

Insertion requires amortized constant time.

Definition at line 596 of file unordered_map.h.

References std::move().

◆ insert() [7/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( const_iterator  ,
node_type &&  __nh 
)
inline

◆ insert() [8/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
void std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( initializer_list< value_type __l)
inline

Attempts to insert a list of elements into the unordered_map.

Parameters
__lA std::initializer_list<value_type> of elements to be inserted.

Complexity similar to that of the range constructor.

Definition at line 627 of file unordered_map.h.

◆ insert() [9/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
insert_return_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( node_type &&  __nh)
inline

◆ insert() [10/10]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
std::pair<iterator, bool> std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert ( value_type &&  __x)
inline

Attempts to insert a std::pair into the unordered_map.

Parameters
__xPair to be inserted (see std::make_pair for easy creation of pairs).
Returns
A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the unordered_map. An unordered_map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the unordered_map.

Insertion requires amortized constant time.

Definition at line 557 of file unordered_map.h.

References std::move().

◆ insert_or_assign() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename _Obj >
pair<iterator, bool> std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert_or_assign ( const key_type __k,
_Obj &&  __obj 
)
inline

Attempts to insert a std::pair into the unordered_map.

Parameters
__kKey to use for finding a possibly existing pair in the map.
__objArgument used to generate the .second for a pair instance.
Returns
A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to insert a (key, value) pair into the unordered_map. An unordered_map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the unordered_map. If the pair was already in the unordered_map, the .second of the pair is assigned from __obj.

Insertion requires amortized constant time.

Definition at line 654 of file unordered_map.h.

References std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::cend().

◆ insert_or_assign() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename _Obj >
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::insert_or_assign ( const_iterator  __hint,
const key_type __k,
_Obj &&  __obj 
)
inline

Attempts to insert a std::pair into the unordered_map.

Parameters
__hintAn iterator that serves as a hint as to where the pair should be inserted.
__kKey to use for finding a possibly existing pair in the unordered_map.
__objArgument used to generate the .second for a pair instance.
Returns
An iterator that points to the element with key of __x (may or may not be the pair passed in).

This function is not concerned about whether the insertion took place, and thus does not return a boolean like the single-argument insert() does.
If the pair was already in the unordered map, the .second of the pair is assigned from __obj. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints for more on hinting.

Insertion requires amortized constant time.

Definition at line 703 of file unordered_map.h.

◆ key_eq()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
key_equal std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::key_eq ( ) const
inline

Returns the key comparison object with which the unordered_map was constructed.

Definition at line 850 of file unordered_map.h.

◆ load_factor()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
float std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::load_factor ( ) const
inlinenoexcept

Returns the average number of elements per bucket.

Definition at line 1090 of file unordered_map.h.

◆ max_bucket_count()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
size_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::max_bucket_count ( ) const
inlinenoexcept

Returns the maximum number of buckets of the unordered_map.

Definition at line 1013 of file unordered_map.h.

◆ max_load_factor() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
float std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::max_load_factor ( ) const
inlinenoexcept

Returns a positive number that the unordered_map tries to keep the load factor less than or equal to.

Definition at line 1096 of file unordered_map.h.

◆ max_load_factor() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
void std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::max_load_factor ( float  __z)
inline

Change the unordered_map maximum load factor.

Parameters
__zThe new maximum load factor.

Definition at line 1104 of file unordered_map.h.

◆ max_size()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
size_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::max_size ( ) const
inlinenoexcept

Returns the maximum size of the unordered_map.

Definition at line 315 of file unordered_map.h.

◆ operator=() [1/3]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
unordered_map& std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::operator= ( const unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc > &  )
default

Copy assignment operator.

◆ operator=() [2/3]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
unordered_map& std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::operator= ( initializer_list< value_type __l)
inline

Unordered_map list assignment operator.

Parameters
__lAn initializer_list.

This function fills an unordered_map with copies of the elements in the initializer list __l.

Note that the assignment completely changes the unordered_map and that the resulting unordered_map's size is the same as the number of elements assigned.

Definition at line 290 of file unordered_map.h.

◆ operator=() [3/3]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
unordered_map& std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::operator= ( unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc > &&  )
default

Move assignment operator.

◆ operator[]() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
mapped_type& std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::operator[] ( const key_type __k)
inline

Subscript ( [] ) access to unordered_map data.

Parameters
__kThe key for which data should be retrieved.
Returns
A reference to the data of the (key,data) pair.

Allows for easy lookup with the subscript ( [] )operator. Returns data associated with the key specified in subscript. If the key does not exist, a pair with that key is created using default values, which is then returned.

Lookup requires constant time.

Definition at line 979 of file unordered_map.h.

◆ operator[]() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
mapped_type& std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::operator[] ( key_type &&  __k)
inline

Subscript ( [] ) access to unordered_map data.

Parameters
__kThe key for which data should be retrieved.
Returns
A reference to the data of the (key,data) pair.

Allows for easy lookup with the subscript ( [] )operator. Returns data associated with the key specified in subscript. If the key does not exist, a pair with that key is created using default values, which is then returned.

Lookup requires constant time.

Definition at line 983 of file unordered_map.h.

References std::move().

◆ rehash()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
void std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::rehash ( size_type  __n)
inline

May rehash the unordered_map.

Parameters
__nThe new number of buckets.

Rehash will occur only if the new number of buckets respect the unordered_map maximum load factor.

Definition at line 1115 of file unordered_map.h.

◆ reserve()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
void std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::reserve ( size_type  __n)
inline

Prepare the unordered_map for a specified number of elements.

Parameters
__nNumber of elements required.

Same as rehash(ceil(n / max_load_factor())).

Definition at line 1126 of file unordered_map.h.

◆ size()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
size_type std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::size ( ) const
inlinenoexcept

Returns the size of the unordered_map.

Definition at line 310 of file unordered_map.h.

◆ swap()

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
void std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::swap ( unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc > &  __x)
inlinenoexcept

Swaps data with another unordered_map.

Parameters
__xAn unordered_map of the same element and allocator types.

This exchanges the elements between two unordered_map in constant time. Note that the global std::swap() function is specialized such that std::swap(m1,m2) will feed to this function.

Definition at line 804 of file unordered_map.h.

◆ try_emplace() [1/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename... _Args>
pair<iterator, bool> std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::try_emplace ( const key_type __k,
_Args &&...  __args 
)
inline

Attempts to build and insert a std::pair into the unordered_map.

Parameters
__kKey to use for finding a possibly existing pair in the unordered_map.
__argsArguments used to generate the .second for a new pair instance.
Returns
A pair, of which the first element is an iterator that points to the possibly inserted pair, and the second is a bool that is true if the pair was actually inserted.

This function attempts to build and insert a (key, value) pair into the unordered_map. An unordered_map relies on unique keys and thus a pair is only inserted if its first element (the key) is not already present in the unordered_map. If a pair is not inserted, this function has no effect.

Insertion requires amortized constant time.

Definition at line 471 of file unordered_map.h.

References std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::cend().

◆ try_emplace() [2/2]

template<typename _Key , typename _Tp , typename _Hash = hash<_Key>, typename _Pred = equal_to<_Key>, typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
template<typename... _Args>
iterator std::unordered_map< _Key, _Tp, _Hash, _Pred, _Alloc >::try_emplace ( const_iterator  __hint,
const key_type __k,
_Args &&...  __args 
)
inline

Attempts to build and insert a std::pair into the unordered_map.

Parameters
__hintAn iterator that serves as a hint as to where the pair should be inserted.
__kKey to use for finding a possibly existing pair in the unordered_map.
__argsArguments used to generate the .second for a new pair instance.
Returns
An iterator that points to the element with key of the std::pair built from __args (may or may not be that std::pair).

This function is not concerned about whether the insertion took place, and thus does not return a boolean like the single-argument emplace() does. However, if insertion did not take place, this function has no effect. Note that the first parameter is only a hint and can potentially improve the performance of the insertion process. A bad hint would cause no gains in efficiency.

See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints for more on hinting.

Insertion requires amortized constant time.

Definition at line 515 of file unordered_map.h.


The documentation for this class was generated from the following file: