Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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object::operator[]

Access or insert the specified element.

Synopsis
value&
operator\[\](
    string_view key);
Description

Returns a reference to the value that is mapped to a key equivalent to key, performing an insertion of a null value if such key does not already exist.

If an insertion occurs and results in a rehashing of the container, all iterators are invalidated. Otherwise iterators are not affected. References are not invalidated. Rehashing occurs only if the new number of elements is greater than capacity().

Complexity

Constant on average, worst case linear in size().

Exception Safety

Strong guarantee. Calls to memory_resource::allocate may throw.

Return Value

A reference to the mapped value.

Parameters

Name

Description

key

The key of the element to find.


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