QLinkedList Class Reference
[Модуль QtCore]
The QLinkedList class is a template class that provides linked lists. Далее...
#include <QLinkedList> Inherited by Q3ValueList.
Замечание: все функции этого класса реентерабильны.
Открытые типы
Открытые функции
Статические открытые члены
- QLinkedList<T> fromStdList ( const std::list<T> & list )
Связанные нечлены класса
- QDataStream & operator<< ( QDataStream & out, const QLinkedList<T> & list )
- QDataStream & operator>> ( QDataStream & in, QLinkedList<T> & list )
Подробное описание
The QLinkedList class is a template class that provides linked lists.
QLinkedList<T> is one of Qt's generic container classes. It stores a list of values and provides iterator-based access as well as constant time insertions and removals.
QList<T>, QLinkedList<T>, and QVector<T> provide similar functionality. Here's an overview:
- For most purposes, QList is the right class to use. Its index-based API is more convenient than QLinkedList's iterator-based API, and it is usually faster than QVector because of the way it stores its items in memory (see Algorithmic Complexity for details). It also expands to less code in your executable.
- If you need a real linked list, with guarantees of constant time insertions in the middle of the list and iterators to items rather than indexes, use QLinkedList.
- If you want the items to occupy adjacent memory positions, use QVector.
Here's an example of a QLinkedList that stores integers and a QLinkedList that stores QTime values:
QLinkedList<int> integerList;
QLinkedList<QTime> timeList;
QLinkedList stores a list of items. The default constructor creates an empty list. To insert items into the list, you can use operator<<():
QLinkedList<QString> list;
list << "one" << "two" << "three";
If you want to get the first or last item in a linked list, use first() or last(). If you want to remove an item from either end of the list, use removeFirst() or removeLast(). If you want to remove all occurrences of a given value in the list, use removeAll().
A common requirement is to remove the first or last item in the list and do something with it. For this, QLinkedList provides takeFirst() and takeLast(). Here's a loop that removes the items from a list one at a time and calls delete on them:
QLinkedList<QWidget *> list;
...
while (!list.isEmpty())
delete list.takeFirst();
QLinkedList's value type must be an assignable data type. This covers most data types that are commonly used, but the compiler won't let you, for example, store a QWidget as a value; instead, store a QWidget *. A few functions have additional requirements; for example, contains() and removeAll() expect the value type to support operator==(). These requirements are documented on a per-function basis.
If you want to insert, modify, or remove items in the middle of the list, you must use an iterator. QLinkedList provides both Java-style iterators (QLinkedListIterator and QMutableLinkedListIterator) and STL-style iterators (QLinkedList::const_iterator and QLinkedList::iterator). See the documentation for these classes for details.
See also QLinkedListIterator, QMutableLinkedListIterator, QList, and QVector.
Описание типов-членов
typedef QLinkedList::ConstIterator
Qt-style synonym for QLinkedList::const_iterator.
typedef QLinkedList::Iterator
Qt-style synonym for QLinkedList::iterator.
typedef QLinkedList::const_pointer
Typedef for const T *. Provided for STL compatibility.
typedef QLinkedList::const_reference
Typedef for const T &. Provided for STL compatibility.
typedef QLinkedList::difference_type
Typedef for ptrdiff_t. Provided for STL compatibility.
typedef QLinkedList::pointer
Typedef for T *. Provided for STL compatibility.
typedef QLinkedList::reference
Typedef for T &. Provided for STL compatibility.
typedef QLinkedList::size_type
Typedef for int. Provided for STL compatibility.
typedef QLinkedList::value_type
Typedef for T. Provided for STL compatibility.
Описание функций-членов
QLinkedList::QLinkedList ()
Constructs an empty list.
QLinkedList::QLinkedList ( const QLinkedList<T> & other )
Создаёт копию other.
This operation occurs in constant time, because QLinkedList is implicitly shared. This makes returning a QLinkedList from a function very fast. If a shared instance is modified, it will be copied (copy-on-write), and this takes linear time.
Смотрите также operator=().
QLinkedList::~QLinkedList ()
Destroys the list. References to the values in the list, and all iterators over this list, become invalid.
void QLinkedList::append ( const T & value )
Inserts value at the end of the list.
Пример:
QLinkedList<QString> list;
list.append("one");
list.append("two");
list.append("three");
This is the same as list.insert(end(), value).
See also operator<<(), prepend(), and insert().
T & QLinkedList::back ()
Эта функция обеспечивает совместимость с STL. It is equivalent to last().
const T & QLinkedList::back () const
Это перегруженная функция.
iterator QLinkedList::begin ()
Returns an STL-style iterator pointing to the first item in the list.
See also constBegin() and end().
Это перегруженная функция.
void QLinkedList::clear ()
Removes all the items in the list.
See also removeAll().
const_iterator QLinkedList::constBegin () const
Returns a const STL-style iterator pointing to the first item in the list.
See also begin() and constEnd().
const_iterator QLinkedList::constEnd () const
Returns a const STL-style iterator pointing to the imaginary item after the last item in the list.
See also constBegin() and end().
bool QLinkedList::contains ( const T & value ) const
Returns true if the list contains an occurrence of value; otherwise returns false.
This function requires the value type to have an implementation of operator==().
See also QLinkedListIterator::findNext() and QLinkedListIterator::findPrevious().
int QLinkedList::count ( const T & value ) const
Returns the number of occurrences of value in the list.
This function requires the value type to have an implementation of operator==().
Смотрите также contains().
int QLinkedList::count () const
То же, что и size().
bool QLinkedList::empty () const
Эта функция обеспечивает совместимость с STL. It is equivalent to isEmpty() and returns true if the list is empty.
iterator QLinkedList::end ()
Returns an STL-style iterator pointing to the imaginary item after the last item in the list.
See also begin() and constEnd().
Это перегруженная функция.
bool QLinkedList::endsWith ( const T & value ) const
Returns true if the list is not empty and its last item is equal to value; otherwise returns false.
Эта функция была введена в Qt 4.5.
See also isEmpty() and last().
Removes the item pointed to by the iterator pos from the list, and returns an iterator to the next item in the list (which may be end()).
Смотрите также insert().
Это перегруженная функция.
Removes all the items from begin up to (but not including) end.
T & QLinkedList::first ()
Returns a reference to the first item in the list. This function assumes that the list isn't empty.
See also last() and isEmpty().
const T & QLinkedList::first () const
Это перегруженная функция.
QLinkedList<T> QLinkedList::fromStdList ( const std::list<T> & list ) [static]
Returns a QLinkedList object with the data contained in list. The order of the elements in the QLinkedList is the same as in list.
Пример:
std::list<double> stdlist;
list.push_back(1.2);
list.push_back(0.5);
list.push_back(3.14);
QLinkedList<double> list = QLinkedList<double>::fromStdList(stdlist);
Эта функция была введена в Qt 4.1.
See also toStdList().
T & QLinkedList::front ()
Эта функция обеспечивает совместимость с STL. It is equivalent to first().
const T & QLinkedList::front () const
Это перегруженная функция.
iterator QLinkedList::insert ( iterator before, const T & value )
Inserts value in front of the item pointed to by the iterator before. Returns an iterator pointing at the inserted item.
See also erase().
bool QLinkedList::isEmpty () const
Возвращает true, если список не содержит элементов; в противном случае возвращается false.
Смотрите также size().
T & QLinkedList::last ()
Returns a reference to the last item in the list. This function assumes that the list isn't empty.
See also first() and isEmpty().
const T & QLinkedList::last () const
Это перегруженная функция.
void QLinkedList::pop_back ()
Эта функция обеспечивает совместимость с STL. It is equivalent to removeLast().
void QLinkedList::pop_front ()
Эта функция обеспечивает совместимость с STL. It is equivalent to removeFirst().
void QLinkedList::prepend ( const T & value )
Inserts value at the beginning of the list.
Пример:
QLinkedList<QString> list;
list.prepend("one");
list.prepend("two");
list.prepend("three");
This is the same as list.insert(begin(), value).
Смотрите также append() и insert().
void QLinkedList::push_back ( const T & value )
Эта функция обеспечивает совместимость с STL. It is equivalent to append(value).
void QLinkedList::push_front ( const T & value )
Эта функция обеспечивает совместимость с STL. It is equivalent to prepend(value).
int QLinkedList::removeAll ( const T & value )
Removes all occurrences of value in the list.
Пример:
QList<QString> list;
list << "sun" << "cloud" << "sun" << "rain";
list.removeAll("sun");
This function requires the value type to have an implementation of operator==().
Смотрите также insert().
void QLinkedList::removeFirst ()
Removes the first item in the list.
This is the same as erase(begin()).
See also removeLast() and erase().
void QLinkedList::removeLast ()
Removes the last item in the list.
See also removeFirst() and erase().
bool QLinkedList::removeOne ( const T & value )
Removes the first occurrences of value in the list. Возвращает true, если всё прошло успешно; в противном случае возвращает false.
Пример:
QList<QString> list;
list << "sun" << "cloud" << "sun" << "rain";
list.removeOne("sun");
This function requires the value type to have an implementation of operator==().
Эта функция была введена в Qt 4.4.
Смотрите также insert().
int QLinkedList::size () const
Returns the number of items in the list.
See also isEmpty() and count().
bool QLinkedList::startsWith ( const T & value ) const
Returns true if the list is not empty and its first item is equal to value; otherwise returns false.
Эта функция была введена в Qt 4.5.
See also isEmpty() and first().
T QLinkedList::takeFirst ()
Removes the first item in the list and returns it.
If you don't use the return value, removeFirst() is more efficient.
See also takeLast() and removeFirst().
T QLinkedList::takeLast ()
Removes the last item in the list and returns it.
If you don't use the return value, removeLast() is more efficient.
See also takeFirst() and removeLast().
std::list<T> QLinkedList::toStdList () const
Returns a std::list object with the data contained in this QLinkedList. Пример:
QLinkedList<double> list;
list << 1.2 << 0.5 << 3.14;
std::list<double> stdlist = list.toStdList();
Эта функция была введена в Qt 4.1.
See also fromStdList().
bool QLinkedList::operator!= ( const QLinkedList<T> & other ) const
Returns true if other is not equal to this list; otherwise returns false.
Two lists are considered equal if they contain the same values in the same order.
This function requires the value type to implement operator==().
Смотрите также operator==().
QLinkedList<T> QLinkedList::operator+ ( const QLinkedList<T> & other ) const
Returns a list that contains all the items in this list followed by all the items in the other list.
Смотрите также operator+=().
QLinkedList<T> & QLinkedList::operator+= ( const QLinkedList<T> & other )
Appends the items of the other list to this list and returns a reference to this list.
See also operator+() and append().
QLinkedList<T> & QLinkedList::operator+= ( const T & value )
Это перегруженная функция.
Appends value to the list.
QLinkedList<T> & QLinkedList::operator<< ( const QLinkedList<T> & other )
Appends the items of the other list to this list and returns a reference to this list.
See also operator+=() and append().
QLinkedList<T> & QLinkedList::operator<< ( const T & value )
Это перегруженная функция.
Appends value to the list.
QLinkedList<T> & QLinkedList::operator= ( const QLinkedList<T> & other )
Assigns other to this list and returns a reference to this list.
bool QLinkedList::operator== ( const QLinkedList<T> & other ) const
Returns true if other is equal to this list; otherwise returns false.
Two lists are considered equal if they contain the same values in the same order.
This function requires the value type to implement operator==().
Смотрите также operator!=().
Связанные нечлены класса
QDataStream & operator<< ( QDataStream & out, const QLinkedList<T> & list )
Writes the linked list list to stream out.
This function requires the value type to implement operator<<().
Смотрите также Формат операторов QDataStream.
QDataStream & operator>> ( QDataStream & in, QLinkedList<T> & list )
Reads a linked list from stream in into list.
This function requires the value type to implement operator>>().
Смотрите также Формат операторов QDataStream.
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