std::map::operator[]

 

C++

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Libreria di Utilità

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Algoritmi

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Libreria matematca

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Localizzazione

Espressioni regolari(C++11)

Operazioni atomicche(C++11)

Multithreading(C++11)

 

Contenitori libreria

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

priority_queue

 

std::map

Membri funzioni Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::map

map::~map

map::operator=

map::get_allocator

Elemento accesso Original: Element access The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::at

map::operator[]

Iteratori Original: Iterators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::begin map::cbegin (C++11)

map::end map::cend (C++11)

map::rbegin map::crbegin (C++11)

map::rend map::crend (C++11)

Capacità Original: Capacity The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::empty

map::size

map::max_size

Modificatori Original: Modifiers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::clear

map::insert

map::emplace (C++11)

map::emplace_hint (C++11)

map::erase

map::swap

Lookup Original: Lookup The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::count

map::find

map::equal_range

map::lower_bound

map::upper_bound

Osservatori Original: Observers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::key_comp

map::value_comp

 

T& operator[](const Key& key );	(1)
T& operator[]( Key&& key );	(2)	(dal C++11)

Inserisce un nuovo elemento al contenitore con key come chiave e predefinito al valore costruito mappato e restituisce un riferimento al valore di nuova costruzione mappati. Se un elemento con key chiave esiste già, non viene eseguita e l'inserimento di un riferimento al suo valore mappato viene restituito.

Original:

Inserts a new element to the container using key as the key and default constructed mapped value and returns a reference to the newly constructed mapped value. If an element with key key already exists, no insertion is performed and a reference to its mapped value is returned.

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1)

Esegue sostanza (insert(std::make_pair(key, T())).first)->second.

Original:

Essentially performs (insert(std::make_pair(key, T())).first)->second.

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2)

Esegue sostanza (insert(std::make_pair(std::move(key), T())).first)->second.

Original:

Essentially performs (insert(std::make_pair(std::move(key), T())).first)->second.

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No iterators or references are invalidated.

Parametri

key

-

la chiave dell'elemento da trovare Original: the key of the element to find The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

Valore di ritorno

Riferimento al valore mappato del nuovo elemento se nessun elemento con chiave key esistito. Altrimenti un riferimento al valore mappato dell'elemento esistente viene restituito.

Original:

Reference to the mapped value of the new element if no element with key key existed. Otherwise a reference to the mapped value of the existing element is returned.

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Complessità

Logarithmic in the size of the container.

Vedi anche

at (C++11)	accedere elemento specificato con verifica dei limiti Original: access specified element with bounds checking The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)