A standard container composed of unique keys (containing at most one of each key value) that associates values of another type with the keys.
typedef _Hashtable::key_type key_type
Public typedefs. typedef _Hashtable::value_type value_type
Public typedefs. typedef _Hashtable::mapped_type mapped_type
Public typedefs. typedef _Hashtable::hasher hasher
Public typedefs. typedef _Hashtable::key_equal key_equal
Public typedefs. typedef _Hashtable::allocator_type allocator_type
Public typedefs.
typedef _Hashtable::pointer pointer
Iterator-related typedefs. typedef _Hashtable::const_pointer
const_pointer
Iterator-related typedefs. typedef _Hashtable::reference reference
Iterator-related typedefs. typedef _Hashtable::const_reference
const_reference
Iterator-related typedefs. typedef _Hashtable::iterator iterator
Iterator-related typedefs. typedef _Hashtable::const_iterator
const_iterator
Iterator-related typedefs. typedef _Hashtable::local_iterator
local_iterator
Iterator-related typedefs. typedef _Hashtable::const_local_iterator
const_local_iterator
Iterator-related typedefs. typedef _Hashtable::size_type size_type
Iterator-related typedefs. typedef _Hashtable::difference_type
difference_type
Iterator-related typedefs.
unordered_map ()=default
Default constructor. 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())
Builds an unordered_map from a range. unordered_map (const
allocator_type &__a)
Creates an unordered_map with no elements. unordered_map (const
unordered_map &)=default
Copy constructor. 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())
Builds an unordered_map from an initializer_list. 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())
Default constructor creates no elements. unordered_map
(unordered_map &&)=default
Move constructor. 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)
Returns a read/write iterator pointing to the first bucket element.
size_type bucket (const key_type &__key) const
size_type bucket_count () const noexcept
Returns the number of buckets of the unordered_map. size_type
bucket_size (size_type __n) const
void clear () noexcept
size_type count (const key_type &__x) const
Finds the number of elements. template<typename... _Args>
std::pair< iterator, bool > emplace (_Args
&&... __args)
Attempts to build and insert a std::pair into the unordered_map.
template<typename... _Args> iterator emplace_hint
(const_iterator __pos, _Args &&... __args)
Attempts to build and insert a std::pair into the unordered_map.
_GLIBCXX_NODISCARD bool empty () const noexcept
Returns true if the unordered_map is empty. iterator end ()
noexcept
local_iterator end (size_type __n)
Returns a read/write iterator pointing to one past the last bucket elements.
size_type erase (const key_type &__x)
Erases elements according to the provided key. iterator erase
(const_iterator __first, const_iterator __last)
Erases a [__first,__last) range of elements from an unordered_map.
allocator_type get_allocator () const noexcept
Returns the allocator object used by the unordered_map. hasher
hash_function () const
Returns the hash functor object with which the unordered_map was constructed.
template<typename _InputIterator > void insert (_InputIterator
__first, _InputIterator __last)
A template function that attempts to insert a range of elements. void
insert (initializer_list< value_type > __l)
Attempts to insert a list of elements into the unordered_map. key_equal
key_eq () const
Returns the key comparison object with which the unordered_map was
constructed. float load_factor () const noexcept
Returns the average number of elements per bucket. size_type
max_bucket_count () const noexcept
Returns the maximum number of buckets of the unordered_map. float
max_load_factor () const noexcept
Returns a positive number that the unordered_map tries to keep the load factor
less than or equal to. void max_load_factor (float __z)
Change the unordered_map maximum load factor. size_type max_size
() const noexcept
Returns the maximum size of the unordered_map. unordered_map &
operator= (const unordered_map &)=default
Copy assignment operator. unordered_map & operator=
(initializer_list< value_type > __l)
Unordered_map list assignment operator. unordered_map &
operator= (unordered_map &&)=default
Move assignment operator. void rehash (size_type __n)
May rehash the unordered_map. void reserve (size_type __n)
Prepare the unordered_map for a specified number of elements. size_type
size () const noexcept
Returns the size of the unordered_map. void swap (unordered_map
&__x) noexcept(noexcept(_M_h.swap(__x._M_h)))
Swaps data with another unordered_map.
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)
Attempts to insert a std::pair into the unordered_map. std::pair<
iterator, bool > insert (value_type &&__x)
Attempts to insert a std::pair into the unordered_map. template<typename
_Pair > __enable_if_t< is_constructible< value_type,
_Pair && >::value, pair< iterator, bool >
> insert (_Pair &&__x)
Attempts to insert a std::pair into the unordered_map.
iterator insert (const_iterator __hint, const
value_type &__x)
Attempts to insert a std::pair into the unordered_map. iterator
insert (const_iterator __hint, value_type
&&__x)
Attempts to insert a std::pair into the unordered_map. template<typename
_Pair > __enable_if_t< is_constructible< value_type,
_Pair && >::value, iterator > insert
(const_iterator __hint, _Pair &&__x)
Attempts to insert a std::pair into the unordered_map.
iterator erase (const_iterator __position)
Erases an element from an unordered_map. iterator erase
(iterator __position)
Erases an element from an unordered_map.
iterator find (const key_type &__x)
Tries to locate an element in an unordered_map. const_iterator
find (const key_type &__x) const
Tries to locate an element in an unordered_map.
std::pair< iterator, iterator > equal_range
(const key_type &__x)
Finds a subsequence matching given key. std::pair<
const_iterator, const_iterator > equal_range (const
key_type &__x) const
Finds a subsequence matching given key.
mapped_type & operator[] (const key_type &__k)
Subscript ( [] ) access to unordered_map data. mapped_type
& operator[] (key_type &&__k)
Subscript ( [] ) access to unordered_map data.
mapped_type & at (const key_type &__k)
Access to unordered_map data. const mapped_type & at (const
key_type &__k) const
Access to unordered_map data.
const_local_iterator begin (size_type __n) const
Returns a read-only (constant) iterator pointing to the first bucket element.
const_local_iterator cbegin (size_type __n) const
Returns a read-only (constant) iterator pointing to the first bucket element.
const_local_iterator end (size_type __n) const
Returns a read-only (constant) iterator pointing to one past the last bucket
elements. const_local_iterator cend (size_type __n)
const
Returns a read-only (constant) iterator pointing to one past the last bucket
elements.
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 >
&)
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
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.
Public typedefs.
Definition at line 116 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 126 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 128 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 122 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 124 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 130 of file unordered_map.h.
Public typedefs.
Definition at line 114 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 125 of file unordered_map.h.
Public typedefs.
Definition at line 115 of file unordered_map.h.
Public typedefs.
Definition at line 111 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 127 of file unordered_map.h.
Public typedefs.
Definition at line 113 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 121 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 123 of file unordered_map.h.
Iterator-related typedefs.
Definition at line 129 of file unordered_map.h.
Public typedefs.
Definition at line 112 of file unordered_map.h.
Default constructor.
Default constructor creates no elements.
Parameters
Definition at line 151 of file unordered_map.h.
Builds an unordered_map from a range.
Parameters
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.
Copy constructor.
Move constructor.
Creates an unordered_map with no elements.
Parameters
Definition at line 191 of file unordered_map.h.
Builds an unordered_map from an initializer_list.
Parameters
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.
Access to unordered_map data.
Parameters
Returns
Exceptions
Definition at line 1002 of file unordered_map.h.
Access to unordered_map data.
Parameters
Returns
Exceptions
Definition at line 1006 of file unordered_map.h.
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.
Returns a read/write iterator that points to the first element in the unordered_map.
Definition at line 325 of file unordered_map.h.
Returns a read/write iterator pointing to the first bucket element.
Parameters
Returns
Definition at line 1047 of file unordered_map.h.
Returns a read-only (constant) iterator pointing to the first bucket element.
Parameters
Returns
Definition at line 1058 of file unordered_map.h.
Returns the number of buckets of the unordered_map.
Definition at line 1014 of file unordered_map.h.
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.
Returns a read-only (constant) iterator pointing to the first bucket element.
Parameters
Returns
Definition at line 1062 of file unordered_map.h.
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.
Returns a read-only (constant) iterator pointing to one past the last bucket elements.
Parameters
Returns
Definition at line 1088 of file unordered_map.h.
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 843 of file unordered_map.h.
Finds the number of elements.
Parameters
Returns
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 939 of file unordered_map.h.
Attempts to build and insert a std::pair into the unordered_map.
Parameters
Returns
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.
Attempts to build and insert a std::pair into the unordered_map.
Parameters
Returns
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.
Returns true if the unordered_map is empty.
Definition at line 305 of file unordered_map.h.
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.
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.
Returns a read/write iterator pointing to one past the last bucket elements.
Parameters
Returns
Definition at line 1073 of file unordered_map.h.
Returns a read-only (constant) iterator pointing to one past the last bucket elements.
Parameters
Returns
Definition at line 1084 of file unordered_map.h.
Finds a subsequence matching given key.
Parameters
Returns
This function probably only makes sense for unordered_multimap.
Definition at line 963 of file unordered_map.h.
Finds a subsequence matching given key.
Parameters
Returns
This function probably only makes sense for unordered_multimap.
Definition at line 967 of file unordered_map.h.
Erases elements according to the provided key.
Parameters
Returns
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 815 of file unordered_map.h.
Erases a [__first,__last) range of elements from an unordered_map.
Parameters
Returns
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 833 of file unordered_map.h.
Erases an element from an unordered_map.
Parameters
Returns
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 793 of file unordered_map.h.
Erases an element from an unordered_map.
Parameters
Returns
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 798 of file unordered_map.h.
Tries to locate an element in an unordered_map.
Parameters
Returns
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 921 of file unordered_map.h.
Tries to locate an element in an unordered_map.
Parameters
Returns
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 925 of file unordered_map.h.
Returns the allocator object used by the unordered_map.
Definition at line 298 of file unordered_map.h.
Returns the hash functor object with which the unordered_map was constructed.
Definition at line 897 of file unordered_map.h.
A template function that attempts to insert a range of elements.
Parameters
Complexity similar to that of the range constructor.
Definition at line 645 of file unordered_map.h.
Attempts to insert a std::pair into the unordered_map.
Parameters
Returns
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 592 of file unordered_map.h.
Attempts to insert a std::pair into the unordered_map.
Parameters
Returns
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 580 of file unordered_map.h.
Attempts to insert a std::pair into the unordered_map.
Parameters
Returns
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 630 of file unordered_map.h.
Attempts to insert a std::pair into the unordered_map.
Parameters
Returns
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 619 of file unordered_map.h.
Attempts to insert a std::pair into the unordered_map.
Parameters
Returns
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 625 of file unordered_map.h.
Attempts to insert a list of elements into the unordered_map.
Parameters
Complexity similar to that of the range constructor.
Definition at line 656 of file unordered_map.h.
Attempts to insert a std::pair into the unordered_map.
Parameters
Returns
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 586 of file unordered_map.h.
Returns the key comparison object with which the unordered_map was constructed.
Definition at line 903 of file unordered_map.h.
Returns the average number of elements per bucket.
Definition at line 1096 of file unordered_map.h.
Returns the maximum number of buckets of the unordered_map.
Definition at line 1019 of file unordered_map.h.
Returns a positive number that the unordered_map tries to keep the load factor less than or equal to.
Definition at line 1102 of file unordered_map.h.
Change the unordered_map maximum load factor.
Parameters
Definition at line 1110 of file unordered_map.h.
Returns the maximum size of the unordered_map.
Definition at line 315 of file unordered_map.h.
Copy assignment operator.
Unordered_map list assignment operator.
Parameters
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.
Move assignment operator.
Subscript ( [] ) access to unordered_map data.
Parameters
Returns
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 985 of file unordered_map.h.
Subscript ( [] ) access to unordered_map data.
Parameters
Returns
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 989 of file unordered_map.h.
May rehash the unordered_map.
Parameters
Rehash will occur only if the new number of buckets respect the unordered_map maximum load factor.
Definition at line 1121 of file unordered_map.h.
Prepare the unordered_map for a specified number of elements.
Parameters
Same as rehash(ceil(n / max_load_factor())).
Definition at line 1132 of file unordered_map.h.
Returns the size of the unordered_map.
Definition at line 310 of file unordered_map.h.
Swaps data with another unordered_map.
Parameters
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 857 of file unordered_map.h.
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