bsl::unordered_map

Synopsis

Declared in <bslstl_unorderedmap.h>

template<
    class KEY,
    class VALUE,
    class HASH = bsl::hash<KEY>,
    class EQUAL = bsl::equal_to<KEY>,
    class ALLOCATOR = bsl::allocator<bsl::pair<KEY const, VALUE>>>
class unordered_map;

Description

This class template implements a value-semantic container type holding an unordered set of KEY-VALUE pairs having unique keys that provide a mapping from keys (of template parameter type KEY) to their associated mapped values (of template parameter type VALUE).

This class: * supports a complete set of value-semantic operations * is exception-neutral (agnostic except for the at method) * is alias-safe * is const thread-safe For terminology see {bsldoc_glossary}.

Type Aliases

Name	Description
`allocator_type`	This `typedef` is an alias to the (template parameter) `ALLOCATOR`.
`const_iterator`	This `typedef` is an alias to `HashTableIterator<const value_type>`.
`const_local_iterator`	This `typedef` is an alias to `HashTableBucketIterator<const value_type>`.
`const_pointer`	This `typedef` is an alias to `AllocatorTraits::const_pointer`.
`const_reference`	This `typedef` is an alias to `const value_type&`.
`difference_type`	This `typedef` is an alias to `AllocatorTraits::difference_type`.
`hasher`	This `typedef` is an alias to the (template parameter) `HASH`.
`iterator`	This `typedef` is an alias to `HashTableIterator<value_type>`.
`key_equal`	This `typedef` is an alias to the (template parameter) `EQUAL`.
`key_type`	This `typedef` is an alias to the (template parameter) `KEY`.
`local_iterator`	This `typedef` is an alias to `HashTableBucketIterator<value_type>`.
`mapped_type`	This `typedef` is an alias to the (template parameter) `VALUE`.
`pointer`	This `typedef` is an alias to `AllocatorTraits::pointer`.
`reference`	This `typedef` is an alias to `value_type&`.
`size_type`	This `typedef` is an alias to `AllocatorTraits::size_type`.
`value_type`	This `typedef` is an alias to `bsl::pair<const KEY, VALUE>`.

Member Functions

Name	Description
`unordered_map` [constructor]	Constructors
`~unordered_map` [destructor]	Destroy this object and each of its elements.
`operator=`	Assignment operators
`at`	`at` overloads
`begin`	`begin` overloads
`bucket`	`bucket` overloads
`bucket_count`	Return the number of buckets in the array of buckets maintained by this unordered map.
`bucket_size`	Return the number of elements in the bucket at `index`.
`cbegin`	`cbegin` overloads
`cend`	`cend` overloads
`clear`	Remove all entries from this unordered map.
`contains`	`contains` overloads
`count`	`count` overloads
`emplace`	Emplace a newly constructed element if its key is not already present.
`emplace_hint`	Emplace a newly constructed element at `hint` if its key is missing.
`empty`	Return `true` if this unordered map contains no elements, and `false` otherwise.
`end`	`end` overloads
`equal_range`	`equal_range` overloads
`erase`	`erase` overloads
`find`	`find` overloads
`get_allocator`	Return (a copy of) the allocator used for memory allocation by this unordered map.
`hash_function`	Return (a copy of) the unary hash functor used by this unordered map to generate a hash value (of type `size_type`) for a `key_type` object.
`insert`	`insert` overloads
`insert_or_assign`	`insert_or_assign` overloads
`insert_range`	Insert each element of `range` whose key is not already present.
`key_eq`	Return (a copy of) binary the key-equality functor used by this unordered map that returns `true` if two `key_type` objects are equivalent, and `false` otherwise.
`load_factor`	Return the current load factor of this unordered map.
`max_bucket_count`	Return a theoretical upper bound on the number of buckets.
`max_load_factor`	`max_load_factor` overloads
`max_size`	Return a theoretical upper bound on the size of this unordered map.
`operator[]`	Subscript operators
`rehash`	Rehash this unordered map to at least `numBuckets` buckets.
`reserve`	Reserve capacity for at least `numElements` without rehashing.
`size`	Return the number of elements in this unordered map.
`swap`	Exchange the contents of this object with those of `other`.
`try_emplace`	`try_emplace` overloads

Deduction Guides

Name	Description
`unordered_map<KEY, VALUE>`	CTAD guide: deduce `KEY` and `VALUE` from initializer_list `value_type`.
`unordered_map<KEY, VALUE>`	CTAD guide: deduce `KEY` and `VALUE` from initializer_list `value_type`.
`unordered_map<KEY, VALUE>`	CTAD guide: deduce `KEY` and `VALUE` from iterator `value_type`.
`unordered_map<KEY, VALUE>`	CTAD guide: deduce `KEY` and `VALUE` from iterator `value_type`.
`unordered_map<KEY, VALUE, HASH>`	CTAD guide: deduce `KEY` and `VALUE` from initializer_list `value_type`.
`unordered_map<KEY, VALUE, HASH>`	CTAD guide: deduce `KEY` and `VALUE` from iterator `value_type`.
`unordered_map<KEY, VALUE, HASH, EQUAL>`	CTAD guide: deduce `KEY` and `VALUE` from initializer_list `value_type`.
`unordered_map<KEY, VALUE, HASH, EQUAL>`	CTAD guide: deduce `KEY` and `VALUE` from iterator `value_type`.
`unordered_map<KEY, VALUE, HASH, EQUAL, ALLOCATOR>`	CTAD guide: deduce `KEY` and `VALUE` from initializer_list `value_type`.
`unordered_map<KEY, VALUE, HASH, EQUAL, ALLOCATOR>`	CTAD guide: deduce `KEY` and `VALUE` from iterator `value_type`.
`unordered_map<KEY, VALUE, HASH, bsl::equal_to<KEY>, ALLOCATOR>`	CTAD guide: deduce `KEY` and `VALUE` from initializer_list `value_type`.
`unordered_map<KEY, VALUE, HASH, bsl::equal_to<KEY>, ALLOCATOR>`	CTAD guide: deduce `KEY` and `VALUE` from iterator `value_type`.
`unordered_map<KEY, VALUE, bsl::hash<KEY>, bsl::equal_to<KEY>, ALLOCATOR>`	CTAD guide: deduce `KEY` and `VALUE` from initializer_list `value_type`.
`unordered_map<KEY, VALUE, bsl::hash<KEY>, bsl::equal_to<KEY>, ALLOCATOR>`	CTAD guide: deduce `KEY` and `VALUE` from initializer_list `value_type`.
`unordered_map<KEY, VALUE, bsl::hash<KEY>, bsl::equal_to<KEY>, ALLOCATOR>`	CTAD guide: deduce `KEY` and `VALUE` from iterator `value_type`.
`unordered_map<KEY, VALUE, bsl::hash<KEY>, bsl::equal_to<KEY>, ALLOCATOR>`	CTAD guide: deduce `KEY` and `VALUE` from iterator `value_type`.

Friends

Name	Description
`bsl::operator==`	Return `true` if `lhs` and `rhs` have the same value, and `false` otherwise.

Non-Member Functions

Name	Description
`erase_if`	Erase every element of `m` that satisfies `predicate`.
`operator==`	Return `true` if `lhs` and `rhs` have the same value, and `false` otherwise.
`swap`	Exchange the contents of `a` with those of `b`.