QMultiMap Class ReferenceThe QMultiMap class is a convenience QMap subclass that provides multi-valued maps. Далее... #include <QMultiMap> Inherits: QMap<Key, T>. Замечание: Все функции в этом классе реентерабельны. Открытые функции
Подробное описаниеThe QMultiMap class is a convenience QMap subclass that provides multi-valued maps. QMultiMap<Key, T> is one of Qt's generic container classes. It inherits QMap and extends it with a few convenience functions that make it more suitable than QMap for storing multi-valued maps. A multi-valued map is a map that allows multiple values with the same key; QMap normally doesn't allow that, unless you call QMap::insertMulti(). Because QMultiMap inherits QMap, all of QMap's functionality also applies to QMultiMap. For example, you can use isEmpty() to test whether the map is empty, and you can traverse a QMultiMap using QMap's iterator classes (for example, QMapIterator). But in addition, it provides an insert() function that corresponds to QMap::insertMulti(), and a replace() function that corresponds to QMap::insert(). It also provides convenient operator+() and operator+=(). Пример: QMultiMap<QString, int> map1, map2, map3; map1.insert("plenty", 100); map1.insert("plenty", 2000); // map1.size() == 2 map2.insert("plenty", 5000); // map2.size() == 1 map3 = map1 + map2; // map3.size() == 3 Unlike QMap, QMultiMap provides no operator[]. Use value() or replace() if you want to access the most recently inserted item with a certain key. If you want to retrieve all the values for a single key, you can use values(const Key &key), which returns a QList<T>: QList<int> values = map.values("plenty"); for (int i = 0; i < values.size(); ++i) cout << values.at(i) << endl; The items that share the same key are available from most recently to least recently inserted. If you prefer the STL-style iterators, you can call find() to get the iterator for the first item with a key and iterate from there: QMultiMap<QString, int>::iterator i = map.find("plenty"); while (i != map.end() && i.key() == "plenty") { cout << i.value() << endl; ++i; } QMultiMap's key and value data types must be assignable data types. This covers most data types you are likely to encounter, but the compiler won't let you, for example, store a QWidget as a value; instead, store a QWidget *. In addition, QMultiMap's key type must provide operator<(). See the QMap documentation for details. See also QMap, QMapIterator, QMutableMapIterator, and QMultiHash. Описание функций-членовQMultiMap::QMultiMap ()Constructs an empty map. QMultiMap::QMultiMap ( const QMap<Key, T> & other )Constructs a copy of other (which can be a QMap or a QMultiMap). Смотрите также operator=(). QMap<Key, T>::const_iterator QMultiMap::constFind ( const Key & key, const T & value ) constReturns an iterator pointing to the item with key key and the value value in the map. If the map contains no such item, the function returns constEnd(). Эта функция была введена в Qt 4.3. See also QMap::constFind(). QMap<Key, T>::const_iterator QMultiMap::constFind ( const Key & key ) constЭто перегруженная функция. See also QMap::constFind(). bool QMultiMap::contains ( const Key & key, const T & value ) constReturns true if the map contains an item with key key and value value; otherwise returns false. Эта функция была введена в Qt 4.3. See also QMap::contains(). bool QMultiMap::contains ( const Key & key ) constЭто перегруженная функция. See also QMap::contains(). int QMultiMap::count ( const Key & key, const T & value ) constReturns the number of items with key key and value value. Эта функция была введена в Qt 4.3. See also QMap::count(). int QMultiMap::count ( const Key & key ) constЭто перегруженная функция. See also QMap::count(). int QMultiMap::count () constЭто перегруженная функция. See also QMap::count(). QMap<Key, T>::iterator QMultiMap::find ( const Key & key, const T & value )Returns an iterator pointing to the item with key key and value value in the map. If the map contains no such item, the function returns end(). If the map contains multiple items with key key, this function returns an iterator that points to the most recently inserted value. Эта функция была введена в Qt 4.3. See also QMap::find(). QMap<Key, T>::iterator QMultiMap::find ( const Key & key )Это перегруженная функция. See also QMap::find(). QMap<Key, T>::const_iterator QMultiMap::find ( const Key & key, const T & value ) constЭто перегруженная функция. Returns a const iterator pointing to the item with the given key and value in the map. If the map contains no such item, the function returns end(). If the map contains multiple items with the specified key, this function returns a const iterator that points to the most recently inserted value. Эта функция была введена в Qt 4.3. See also QMap::find(). QMap<Key, T>::const_iterator QMultiMap::find ( const Key & key ) constЭто перегруженная функция. Эта функция была введена в Qt 4.3. See also QMap::find(). QMap<Key, T>::iterator QMultiMap::insert ( const Key & key, const T & value )Inserts a new item with the key key and a value of value. If there is already an item with the same key in the map, this function will simply create a new one. (This behavior is different from replace(), which overwrites the value of an existing item.) Смотрите также replace(). int QMultiMap::remove ( const Key & key, const T & value )Removes all the items that have the key key and the value value from the map. Returns the number of items removed. Эта функция была введена в Qt 4.3. See also QMap::remove(). int QMultiMap::remove ( const Key & key )Это перегруженная функция. See also QMap::remove(). QMap<Key, T>::iterator QMultiMap::replace ( const Key & key, const T & value )Inserts a new item with the key key and a value of value. If there is already an item with the key key, that item's value is replaced with value. If there are multiple items with the key key, the most recently inserted item's value is replaced with value. Смотрите также insert(). QMultiMap QMultiMap::operator+ ( const QMultiMap & other ) constReturns a map that contains all the items in this map in addition to all the items in other. If a key is common to both maps, the resulting map will contain the key multiple times. Смотрите также operator+=(). QMultiMap & QMultiMap::operator+= ( const QMultiMap & other )Inserts all the items in the other map into this map and returns a reference to this map. |
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