size_type count( const Key& key ) const;
(1) (since C++11)

Returns the number of elements with key that compares equal to the specified argument key, which is either 1 or 0 since this container does not allow duplicates.


key - key value of the elements to count

Return value

Number of elements with key key, that is either 1 or 0.


Constant on average, worst case linear in the size of the container.

See also

finds element with specific key
(public member function)
returns range of elements matching a specific key
(public member function)

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