# std::unordered_map<Key,T,Hash,KeyEqual,Allocator>::at

From cppreference.com
< cpp‎ | container‎ | unordered map

T& at( const Key& key ); | (1) | (since C++11)
const T& at( const Key& key ) const; | (2) | (since C++11)

Returns a reference to the mapped value of the element with key equivalent to key. If no such element exists, an exception of type std::out_of_range is thrown.

### Parameters

key | - | the key of the element to find

### Return value

Reference to the mapped value of the requested element.

### Exceptions

std::out_of_range if the container does not have an element with the specified key.

### Complexity

Average case: constant, worst case: linear in size.

### See also

operator[] (C++11) | access or insert specified element (public member function)

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_map/at&oldid=131156"