object::insert_or_assign
Insert an element or assign to an existing element.
Synopsis
template<
class M>
std::pair< object::iterator, bool >
insert_or_assign(
string_view key,
M&& m);Description
If the key equal to key already exists in the container, assigns std::forward<M>(m) to the mapped_type corresponding to that key. Otherwise, inserts the as if by insert, constructing it using value_type(key, std::forward<M>(m)).
If insertion would result in the new number of elements exceeding capacity(), a reallocation and a rehashing occur. In that case all iterators and references are invalidated. Otherwise, they are not affected.
Complexity
Constant on average, worst case linear in size().
Exception Safety
Strong guarantee. Calls to memory_resource::allocate may throw.
Return Value
A std::pair where first is an iterator to the existing or inserted element, and second is true if the insertion took place or false if the assignment took place.
Parameters
| Name | Description |
|---|---|
|
The key used for lookup and insertion. |
|
The value to insert or assign. |
Exceptions
| Type | Thrown On |
|---|---|
|
The size of a key would exceed |