object::at (3 of 3 overloads)

Access the specified element, with bounds checking.

value const&
at(
    string_view key,
    boost::source_location const& loc = BOOST_CURRENT_LOCATION) const&;

Returns a reference to the mapped value of the element that matches key, otherwise throws.

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

Strong guarantee.

A reference to the mapped value.

Name	Description
`key`	The key of the element to find.
`loc`	`source_location` to use in thrown exception; the source location of the call site by default.

Type	Thrown On
boost::system::system_error	if no such element exists.