<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<!-- qlist.cpp -->
<head>
<title>Qt 4.6: QList Class Reference</title>
<link href="classic.css" rel="stylesheet" type="text/css" />
</head>
<body>
<a name="//apple_ref/cpp/cl//QList"></a>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td align="left" valign="top" width="32"><a href="http://qt.nokia.com/"><img src="images/qt-logo.png" align="left" border="0" /></a></td>
<td width="1"> </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a> · <a href="classes.html"><font color="#004faf">All Classes</font></a> · <a href="functions.html"><font color="#004faf">All Functions</font></a> · <a href="overviews.html"><font color="#004faf">Overviews</font></a></td></tr></table><h1 class="title">QList Class Reference<br /><span class="small-subtitle">[<a href="qtcore.html">QtCore</a> module]</span>
</h1>
<p>The QList class is a template class that provides lists. <a href="#details">More...</a></p>
<pre> #include <QList></pre><p>Inherited by <a href="qitemselection.html">QItemSelection</a>, <a href="qqueue.html">QQueue</a>, <a href="qsignalspy.html">QSignalSpy</a>, <a href="qstringlist.html">QStringList</a>, and <a href="qtesteventlist.html">QTestEventList</a>.</p>
<p><b>Note:</b> All functions in this class are <a href="threads-reentrancy.html#reentrant">reentrant</a>.</p>
<ul>
<li><a href="qlist-members.html">List of all members, including inherited members</a></li>
<li><a href="qlist-qt3.html">Qt 3 support members</a></li>
</ul>
<hr />
<a name="public-types"></a>
<h2>Public Types</h2>
<table class="alignedsummary" border="0" cellpadding="0" cellspacing="0" width="100%">
<tr><td class="memItemLeft" align="right" valign="top">class </td><td class="memItemRight" valign="bottom"><b><a href="qlist-const-iterator.html">const_iterator</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">class </td><td class="memItemRight" valign="bottom"><b><a href="qlist-iterator.html">iterator</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">typedef </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#ConstIterator-typedef">ConstIterator</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">typedef </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#Iterator-typedef">Iterator</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">typedef </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#const_pointer-typedef">const_pointer</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">typedef </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#const_reference-typedef">const_reference</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">typedef </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#difference_type-typedef">difference_type</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">typedef </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#pointer-typedef">pointer</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">typedef </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#reference-typedef">reference</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">typedef </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#size_type-typedef">size_type</a></b></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">typedef </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#value_type-typedef">value_type</a></b></td></tr>
</table>
<hr />
<a name="public-functions"></a>
<h2>Public Functions</h2>
<table class="alignedsummary" border="0" cellpadding="0" cellspacing="0" width="100%">
<tr><td class="memItemLeft" align="right" valign="top"></td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#QList">QList</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top"></td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#QList-2">QList</a></b> ( const QList<T> & <i>other</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top"></td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#dtor.QList">~QList</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#append">append</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#append-2">append</a></b> ( const QList<T> & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#at">at</a></b> ( int <i>i</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#back">back</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#back-2">back</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">iterator </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#begin">begin</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const_iterator </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#begin-2">begin</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#clear">clear</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const_iterator </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#constBegin">constBegin</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const_iterator </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#constEnd">constEnd</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#contains">contains</a></b> ( const T & <i>value</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#count">count</a></b> ( const T & <i>value</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#count-2">count</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#empty">empty</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">iterator </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#end">end</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const_iterator </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#end-2">end</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#endsWith">endsWith</a></b> ( const T & <i>value</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">iterator </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#erase">erase</a></b> ( iterator <i>pos</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">iterator </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#erase-2">erase</a></b> ( iterator <i>begin</i>, iterator <i>end</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#first">first</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#first-2">first</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#front">front</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#front-2">front</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#indexOf">indexOf</a></b> ( const T & <i>value</i>, int <i>from</i> = 0 ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#insert">insert</a></b> ( int <i>i</i>, const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">iterator </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#insert-2">insert</a></b> ( iterator <i>before</i>, const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#isEmpty">isEmpty</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#last">last</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#last-2">last</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#lastIndexOf">lastIndexOf</a></b> ( const T & <i>value</i>, int <i>from</i> = -1 ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#length">length</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QList<T> </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#mid">mid</a></b> ( int <i>pos</i>, int <i>length</i> = -1 ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#move">move</a></b> ( int <i>from</i>, int <i>to</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#pop_back">pop_back</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#pop_front">pop_front</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#prepend">prepend</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#push_back">push_back</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#push_front">push_front</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#removeAll">removeAll</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#removeAt">removeAt</a></b> ( int <i>i</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#removeFirst">removeFirst</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#removeLast">removeLast</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#removeOne">removeOne</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#replace">replace</a></b> ( int <i>i</i>, const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#size">size</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#startsWith">startsWith</a></b> ( const T & <i>value</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#swap">swap</a></b> ( int <i>i</i>, int <i>j</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#takeAt">takeAt</a></b> ( int <i>i</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#takeFirst">takeFirst</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#takeLast">takeLast</a></b> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QSet<T> </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#toSet">toSet</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">std::list<T> </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#toStdList">toStdList</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QVector<T> </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#toVector">toVector</a></b> () const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#value">value</a></b> ( int <i>i</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#value-2">value</a></b> ( int <i>i</i>, const T & <i>defaultValue</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-not-eq">operator!=</a></b> ( const QList<T> & <i>other</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QList<T> </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-2b">operator+</a></b> ( const QList<T> & <i>other</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QList<T> & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-2b-eq">operator+=</a></b> ( const QList<T> & <i>other</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QList<T> & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-2b-eq-2">operator+=</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QList<T> & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-lt-lt">operator<<</a></b> ( const QList<T> & <i>other</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QList<T> & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-lt-lt-2">operator<<</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QList<T> & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-eq">operator=</a></b> ( const QList<T> & <i>other</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-eq-eq">operator==</a></b> ( const QList<T> & <i>other</i> ) const</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-5b-5d">operator[]</a></b> ( int <i>i</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">const T & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-5b-5d-2">operator[]</a></b> ( int <i>i</i> ) const</td></tr>
</table>
<hr />
<a name="static-public-members"></a>
<h2>Static Public Members</h2>
<table class="alignedsummary" border="0" cellpadding="0" cellspacing="0" width="100%">
<tr><td class="memItemLeft" align="right" valign="top">QList<T> </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#fromSet">fromSet</a></b> ( const QSet<T> & <i>set</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QList<T> </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#fromStdList">fromStdList</a></b> ( const std::list<T> & <i>list</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QList<T> </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#fromVector">fromVector</a></b> ( const QVector<T> & <i>vector</i> )</td></tr>
</table>
<hr />
<a name="related-non-members"></a>
<h2>Related Non-Members</h2>
<table class="alignedsummary" border="0" cellpadding="0" cellspacing="0" width="100%">
<tr><td class="memItemLeft" align="right" valign="top">QDataStream & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-lt-lt-73">operator<<</a></b> ( QDataStream & <i>out</i>, const QList<T> & <i>list</i> )</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">QDataStream & </td><td class="memItemRight" valign="bottom"><b><a href="qlist.html#operator-gt-gt-40">operator>></a></b> ( QDataStream & <i>in</i>, QList<T> & <i>list</i> )</td></tr>
</table>
<a name="details"></a>
<hr />
<h2>Detailed Description</h2>
<p>The QList class is a template class that provides lists.</p>
<p>QList<T> is one of Qt's generic <a href="containers.html#container-classes">container classes</a>. It stores a list of values and provides fast index-based access as well as fast insertions and removals.</p>
<p>QList<T>, <a href="qlinkedlist.html">QLinkedList</a><T>, and <a href="qvector.html">QVector</a><T> provide similar functionality. Here's an overview:</p>
<ul>
<li>For most purposes, QList is the right class to use. Its index-based API is more convenient than <a href="qlinkedlist.html">QLinkedList</a>'s iterator-based API, and it is usually faster than <a href="qvector.html">QVector</a> because of the way it stores its items in memory. It also expands to less code in your executable.</li>
<li>If you need a real linked list, with guarantees of <a href="containers.html#constant-time">constant time</a> insertions in the middle of the list and iterators to items rather than indexes, use <a href="qlinkedlist.html">QLinkedList</a>.</li>
<li>If you want the items to occupy adjacent memory positions, use <a href="qvector.html">QVector</a>.</li>
</ul>
<p>Internally, QList<T> is represented as an array of pointers to items of type T. If T is itself a pointer type or a basic type that is no larger than a pointer, or if T is one of Qt's <a href="implicit-sharing.html#shared-classes">shared classes</a>, then QList<T> stores the items directly in the pointer array. For lists under a thousand items, this array representation allows for very fast insertions in the middle, and it allows index-based access. Furthermore, operations like <a href="qlist.html#prepend">prepend</a>() and <a href="qlist.html#append">append</a>() are very fast, because QList preallocates memory at both ends of its internal array. (See <a href="containers.html#algorithmic-complexity">Algorithmic Complexity</a> for details.) Note, however, that for unshared list items that are larger than a pointer, each append or insert of a new item requires allocating the new item on the heap, and this per item allocation might make <a href="qvector.html">QVector</a> a better choice in cases that do lots of appending or inserting, since <a href="qvector.html">QVector</a> allocates memory for its items in a single heap allocation.</p>
<p>Note that the internal array only ever gets bigger over the life of the list. It never shrinks. The internal array is deallocated by the destructor and by the assignment operator, when one list is assigned to another.</p>
<p>Here's an example of a QList that stores integers and a QList that stores <a href="qdate.html">QDate</a> values:</p>
<pre> QList<int> integerList;
QList<QDate> dateList;</pre>
<p>Qt includes a <a href="qstringlist.html">QStringList</a> class that inherits QList<<a href="qstring.html">QString</a>> and adds a few convenience functions, such as <a href="qstringlist.html#join">QStringList::join</a>() and <a href="qlist-qt3.html#find" class="compat">QStringList::find</a>(). (<a href="qstring.html#split">QString::split</a>() creates QStringLists from strings.)</p>
<p>QList stores a list of items. The default constructor creates an empty list. To insert items into the list, you can use operator<<():</p>
<pre> QList<QString> list;
list << "one" << "two" << "three";
<span class="comment"> // list: ["one", "two", "three"]</span></pre>
<p>QList provides these basic functions to add, move, and remove items: <a href="qlist.html#insert">insert</a>(), <a href="qlist.html#replace">replace</a>(), <a href="qlist.html#removeAt">removeAt</a>(), <a href="qlist.html#move">move</a>(), and <a href="qlist.html#swap">swap</a>(). In addition, it provides the following convenience functions: <a href="qlist.html#append">append</a>(), <a href="qlist.html#prepend">prepend</a>(), <a href="qlist.html#removeFirst">removeFirst</a>(), and <a href="qlist.html#removeLast">removeLast</a>().</p>
<p>QList uses 0-based indexes, just like C++ arrays. To access the item at a particular index position, you can use operator[](). On non-const lists, operator[]() returns a reference to the item and can be used on the left side of an assignment:</p>
<pre> if (list[0] == "Bob")
list[0] = "Robert";</pre>
<p>Because QList is implemented as an array of pointers, this operation is very fast (<a href="containers.html#constant-time">constant time</a>). For read-only access, an alternative syntax is to use <a href="qlist.html#at">at</a>():</p>
<pre> for (int i = 0; i < list.size(); ++i) {
if (list.at(i) == "Jane")
cout << "Found Jane at position " << i << endl;
}</pre>
<p><a href="qlist.html#at">at</a>() can be faster than operator[](), because it never causes a <a href="implicit-sharing.html#deep-copy">deep copy</a> to occur.</p>
<p>A common requirement is to remove an item from a list and do something with it. For this, QList provides <a href="qlist.html#takeAt">takeAt</a>(), <a href="qlist.html#takeFirst">takeFirst</a>(), and <a href="qlist.html#takeLast">takeLast</a>(). Here's a loop that removes the items from a list one at a time and calls <tt>delete</tt> on them:</p>
<pre> QList<QWidget *> list;
...
while (!list.isEmpty())
delete list.takeFirst();</pre>
<p>Inserting and removing items at either ends of the list is very fast (<a href="containers.html#constant-time">constant time</a> in most cases), because QList preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list.</p>
<p>If you want to find all occurrences of a particular value in a list, use <a href="qlist.html#indexOf">indexOf</a>() or <a href="qlist.html#lastIndexOf">lastIndexOf</a>(). The former searches forward starting from a given index position, the latter searches backward. Both return the index of a matching item if they find it; otherwise, they return -1. For example:</p>
<pre> int i = list.indexOf("Jane");
if (i != -1)
cout << "First occurrence of Jane is at position " << i << endl;</pre>
<p>If you simply want to check whether a list contains a particular value, use <a href="qlist.html#contains">contains</a>(). If you want to find out how many times a particular value occurs in the list, use <a href="qlist.html#count">count</a>(). If you want to replace all occurrences of a particular value with another, use <a href="qlist.html#replace">replace</a>().</p>
<p>QList's value type must be an <a href="containers.html#assignable-data-type">assignable data type</a>. This covers most data types that are commonly used, but the compiler won't let you, for example, store a <a href="qwidget.html">QWidget</a> as a value; instead, store a <a href="qwidget.html">QWidget</a> *. A few functions have additional requirements; for example, <a href="qlist.html#indexOf">indexOf</a>() and <a href="qlist.html#lastIndexOf">lastIndexOf</a>() expect the value type to support <tt>operator==()</tt>. These requirements are documented on a per-function basis.</p>
<p>Like the other container classes, QList provides <a href="containers.html#java-style-iterators">Java-style iterators</a> (<a href="qlistiterator.html">QListIterator</a> and <a href="qmutablelistiterator.html">QMutableListIterator</a>) and <a href="containers.html#stl-style-iterators">STL-style iterators</a> (<a href="qlist-const-iterator.html">QList::const_iterator</a> and <a href="qlist-iterator.html">QList::iterator</a>). In practice, these are rarely used, because you can use indexes into the QList. QList is implemented in such a way that direct index-based access is just as fast as using iterators.</p>
<p>QList does <i>not</i> support inserting, prepending, appending or replacing with references to its own values. Doing so will cause your application to abort with an error message.</p>
<p>To make QList as efficient as possible, its member functions don't validate their input before using it. Except for <a href="qlist.html#isEmpty">isEmpty</a>(), member functions always assume the list is <i>not</i> empty. Member functions that take index values as parameters always assume their index value parameters are in the valid range. This means QList member functions can fail. If you define QT_NO_DEBUG when you compile, failures will not be detected. If you <i>don't</i> define QT_NO_DEBUG, failures will be detected using <a href="qtglobal.html#Q_ASSERT">Q_ASSERT</a>() or <a href="qtglobal.html#Q_ASSERT_X">Q_ASSERT_X</a>() with an appropriate message.</p>
<p>To avoid failures when your list can be empty, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling other member functions. If you must pass an index value that might not be in the valid range, check that it is less than the value returned by <a href="qlist.html#size">size</a>() but <i>not</i> less than 0.</p>
<p>See also <a href="qlistiterator.html">QListIterator</a>, <a href="qmutablelistiterator.html">QMutableListIterator</a>, <a href="qlinkedlist.html">QLinkedList</a>, and <a href="qvector.html">QVector</a>.</p>
<hr />
<h2>Member Type Documentation</h2>
<a name="//apple_ref/cpp/tdef/QList/ConstIterator"></a>
<h3 class="fn"><a name="ConstIterator-typedef"></a>typedef QList::ConstIterator</h3>
<p>Qt-style synonym for <a href="qlist-const-iterator.html">QList::const_iterator</a>.</p>
<a name="//apple_ref/cpp/tdef/QList/Iterator"></a>
<h3 class="fn"><a name="Iterator-typedef"></a>typedef QList::Iterator</h3>
<p>Qt-style synonym for <a href="qlist-iterator.html">QList::iterator</a>.</p>
<a name="//apple_ref/cpp/tdef/QList/const_pointer"></a>
<h3 class="fn"><a name="const_pointer-typedef"></a>typedef QList::const_pointer</h3>
<p>Typedef for const T *. Provided for STL compatibility.</p>
<a name="//apple_ref/cpp/tdef/QList/const_reference"></a>
<h3 class="fn"><a name="const_reference-typedef"></a>typedef QList::const_reference</h3>
<p>Typedef for const T &. Provided for STL compatibility.</p>
<a name="//apple_ref/cpp/tdef/QList/difference_type"></a>
<h3 class="fn"><a name="difference_type-typedef"></a>typedef QList::difference_type</h3>
<p>Typedef for ptrdiff_t. Provided for STL compatibility.</p>
<a name="//apple_ref/cpp/tdef/QList/pointer"></a>
<h3 class="fn"><a name="pointer-typedef"></a>typedef QList::pointer</h3>
<p>Typedef for T *. Provided for STL compatibility.</p>
<a name="//apple_ref/cpp/tdef/QList/reference"></a>
<h3 class="fn"><a name="reference-typedef"></a>typedef QList::reference</h3>
<p>Typedef for T &. Provided for STL compatibility.</p>
<a name="//apple_ref/cpp/tdef/QList/size_type"></a>
<h3 class="fn"><a name="size_type-typedef"></a>typedef QList::size_type</h3>
<p>Typedef for int. Provided for STL compatibility.</p>
<a name="//apple_ref/cpp/tdef/QList/value_type"></a>
<h3 class="fn"><a name="value_type-typedef"></a>typedef QList::value_type</h3>
<p>Typedef for T. Provided for STL compatibility.</p>
<hr />
<h2>Member Function Documentation</h2>
<a name="//apple_ref/cpp/instm/QList/QList"></a>
<h3 class="fn"><a name="QList"></a>QList::QList ()</h3>
<p>Constructs an empty list.</p>
<h3 class="fn"><a name="QList-2"></a>QList::QList ( const QList<T> & <i>other</i> )</h3>
<p>Constructs a copy of <i>other</i>.</p>
<p>This operation takes <a href="containers.html#constant-time">constant time</a>, because <a href="qlist.html">QList</a> is <a href="implicit-sharing.html#implicitly-shared">implicitly shared</a>. This makes returning a <a href="qlist.html">QList</a> from a function very fast. If a shared instance is modified, it will be copied (copy-on-write), and that takes <a href="containers.html#linear-time">linear time</a>.</p>
<p>See also <a href="qlist.html#operator-eq">operator=</a>().</p>
<a name="//apple_ref/cpp/instm/QList/~QList"></a>
<h3 class="fn"><a name="dtor.QList"></a>QList::~QList ()</h3>
<p>Destroys the list. References to the values in the list and all iterators of this list become invalid.</p>
<a name="//apple_ref/cpp/instm/QList/append"></a>
<h3 class="fn"><a name="append"></a>void QList::append ( const T & <i>value</i> )</h3>
<p>Inserts <i>value</i> at the end of the list.</p>
<p>Example:</p>
<pre> QList<QString> list;
list.append("one");
list.append("two");
list.append("three");
<span class="comment"> // list: ["one", "two", "three"]</span></pre>
<p>This is the same as list.insert(<a href="qlist.html#size">size</a>(), <i>value</i>).</p>
<p>This operation is typically very fast (<a href="containers.html#constant-time">constant time</a>), because <a href="qlist.html">QList</a> preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list.</p>
<p>See also <a href="qlist.html#operator-lt-lt">operator<<</a>(), <a href="qlist.html#prepend">prepend</a>(), and <a href="qlist.html#insert">insert</a>().</p>
<h3 class="fn"><a name="append-2"></a>void QList::append ( const QList<T> & <i>value</i> )</h3>
<p>This is an overloaded function.</p>
<p>Appends the items of the <i>value</i> list to this list.</p>
<p>This function was introduced in Qt 4.5.</p>
<p>See also <a href="qlist.html#operator-lt-lt">operator<<</a>() and <a href="qlist.html#operator-2b-eq">operator+=</a>().</p>
<a name="//apple_ref/cpp/instm/QList/at"></a>
<h3 class="fn"><a name="at"></a>const T & QList::at ( int <i>i</i> ) const</h3>
<p>Returns the item at index position <i>i</i> in the list. <i>i</i> must be a valid index position in the list (i.e., 0 <= <i>i</i> < <a href="qlist.html#size">size</a>()).</p>
<p>This function is very fast (<a href="containers.html#constant-time">constant time</a>).</p>
<p>See also <a href="qlist.html#value">value</a>() and <a href="qlist.html#operator-5b-5d">operator[]</a>().</p>
<a name="//apple_ref/cpp/instm/QList/back"></a>
<h3 class="fn"><a name="back"></a>T & QList::back ()</h3>
<p>This function is provided for STL compatibility. It is equivalent to <a href="qlist.html#last">last</a>(). The list must not be empty. If the list can be empty, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<h3 class="fn"><a name="back-2"></a>const T & QList::back () const</h3>
<p>This is an overloaded function.</p>
<a name="//apple_ref/cpp/instm/QList/begin"></a>
<h3 class="fn"><a name="begin"></a><a href="qlist-iterator.html">iterator</a> QList::begin ()</h3>
<p>Returns an <a href="containers.html#stl-style-iterators">STL-style iterator</a> pointing to the first item in the list.</p>
<p>See also <a href="qlist.html#constBegin">constBegin</a>() and <a href="qlist.html#end">end</a>().</p>
<h3 class="fn"><a name="begin-2"></a><a href="qlist-const-iterator.html">const_iterator</a> QList::begin () const</h3>
<p>This is an overloaded function.</p>
<a name="//apple_ref/cpp/instm/QList/clear"></a>
<h3 class="fn"><a name="clear"></a>void QList::clear ()</h3>
<p>Removes all items from the list.</p>
<p>See also <a href="qlist.html#removeAll">removeAll</a>().</p>
<a name="//apple_ref/cpp/instm/QList/constBegin"></a>
<h3 class="fn"><a name="constBegin"></a><a href="qlist-const-iterator.html">const_iterator</a> QList::constBegin () const</h3>
<p>Returns a const <a href="containers.html#stl-style-iterators">STL-style iterator</a> pointing to the first item in the list.</p>
<p>See also <a href="qlist.html#begin">begin</a>() and <a href="qlist.html#constEnd">constEnd</a>().</p>
<a name="//apple_ref/cpp/instm/QList/constEnd"></a>
<h3 class="fn"><a name="constEnd"></a><a href="qlist-const-iterator.html">const_iterator</a> QList::constEnd () const</h3>
<p>Returns a const <a href="containers.html#stl-style-iterators">STL-style iterator</a> pointing to the imaginary item after the last item in the list.</p>
<p>See also <a href="qlist.html#constBegin">constBegin</a>() and <a href="qlist.html#end">end</a>().</p>
<a name="//apple_ref/cpp/instm/QList/contains"></a>
<h3 class="fn"><a name="contains"></a>bool QList::contains ( const T & <i>value</i> ) const</h3>
<p>Returns true if the list contains an occurrence of <i>value</i>; otherwise returns false.</p>
<p>This function requires the value type to have an implementation of <tt>operator==()</tt>.</p>
<p>See also <a href="qlist.html#indexOf">indexOf</a>() and <a href="qlist.html#count">count</a>().</p>
<a name="//apple_ref/cpp/instm/QList/count"></a>
<h3 class="fn"><a name="count"></a>int QList::count ( const T & <i>value</i> ) const</h3>
<p>Returns the number of occurrences of <i>value</i> in the list.</p>
<p>This function requires the value type to have an implementation of <tt>operator==()</tt>.</p>
<p>See also <a href="qlist.html#contains">contains</a>() and <a href="qlist.html#indexOf">indexOf</a>().</p>
<h3 class="fn"><a name="count-2"></a>int QList::count () const</h3>
<p>Returns the number of items in the list. This is effectively the same as <a href="qlist.html#size">size</a>().</p>
<a name="//apple_ref/cpp/instm/QList/empty"></a>
<h3 class="fn"><a name="empty"></a>bool QList::empty () const</h3>
<p>This function is provided for STL compatibility. It is equivalent to <a href="qlist.html#isEmpty">isEmpty</a>() and returns true if the list is empty.</p>
<a name="//apple_ref/cpp/instm/QList/end"></a>
<h3 class="fn"><a name="end"></a><a href="qlist-iterator.html">iterator</a> QList::end ()</h3>
<p>Returns an <a href="containers.html#stl-style-iterators">STL-style iterator</a> pointing to the imaginary item after the last item in the list.</p>
<p>See also <a href="qlist.html#begin">begin</a>() and <a href="qlist.html#constEnd">constEnd</a>().</p>
<h3 class="fn"><a name="end-2"></a><a href="qlist-const-iterator.html">const_iterator</a> QList::end () const</h3>
<p>This is an overloaded function.</p>
<a name="//apple_ref/cpp/instm/QList/endsWith"></a>
<h3 class="fn"><a name="endsWith"></a>bool QList::endsWith ( const T & <i>value</i> ) const</h3>
<p>Returns true if this list is not empty and its last item is equal to <i>value</i>; otherwise returns false.</p>
<p>This function was introduced in Qt 4.5.</p>
<p>See also <a href="qlist.html#isEmpty">isEmpty</a>() and <a href="qlist.html#contains">contains</a>().</p>
<a name="//apple_ref/cpp/instm/QList/erase"></a>
<h3 class="fn"><a name="erase"></a><a href="qlist-iterator.html">iterator</a> QList::erase ( <a href="qlist-iterator.html">iterator</a> <i>pos</i> )</h3>
<p>Removes the item associated with the iterator <i>pos</i> from the list, and returns an iterator to the next item in the list (which may be <a href="qlist.html#end">end</a>()).</p>
<p>See also <a href="qlist.html#insert">insert</a>() and <a href="qlist.html#removeAt">removeAt</a>().</p>
<h3 class="fn"><a name="erase-2"></a><a href="qlist-iterator.html">iterator</a> QList::erase ( <a href="qlist-iterator.html">iterator</a> <i>begin</i>, <a href="qlist-iterator.html">iterator</a> <i>end</i> )</h3>
<p>This is an overloaded function.</p>
<p>Removes all the items from <i>begin</i> up to (but not including) <i>end</i>. Returns an iterator to the same item that <i>end</i> referred to before the call.</p>
<a name="//apple_ref/cpp/instm/QList/first"></a>
<h3 class="fn"><a name="first"></a>T & QList::first ()</h3>
<p>Returns a reference to the first item in the list. The list must not be empty. If the list can be empty, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<p>See also <a href="qlist.html#last">last</a>() and <a href="qlist.html#isEmpty">isEmpty</a>().</p>
<h3 class="fn"><a name="first-2"></a>const T & QList::first () const</h3>
<p>This is an overloaded function.</p>
<a name="//apple_ref/cpp/clm/QList/fromSet"></a>
<h3 class="fn"><a name="fromSet"></a>QList<T> QList::fromSet ( const <a href="qset.html">QSet</a><T> & <i>set</i> ) <tt> [static]</tt></h3>
<p>Returns a <a href="qlist.html">QList</a> object with the data contained in <i>set</i>. The order of the elements in the <a href="qlist.html">QList</a> is undefined.</p>
<p>Example:</p>
<pre> QSet<int> set;
set << 20 << 30 << 40 << ... << 70;
QList<int> list = QList<int>::fromSet(set);
qSort(list);</pre>
<p>See also <a href="qlist.html#fromVector">fromVector</a>(), <a href="qlist.html#toSet">toSet</a>(), <a href="qset.html#toList">QSet::toList</a>(), and <a href="qtalgorithms.html#qSort">qSort</a>().</p>
<a name="//apple_ref/cpp/clm/QList/fromStdList"></a>
<h3 class="fn"><a name="fromStdList"></a>QList<T> QList::fromStdList ( const std::list<T> & <i>list</i> ) <tt> [static]</tt></h3>
<p>Returns a <a href="qlist.html">QList</a> object with the data contained in <i>list</i>. The order of the elements in the <a href="qlist.html">QList</a> is the same as in <i>list</i>.</p>
<p>Example:</p>
<pre> std::list<double> stdlist;
list.push_back(1.2);
list.push_back(0.5);
list.push_back(3.14);
QList<double> list = QList<double>::fromStdList(stdlist);</pre>
<p>See also <a href="qlist.html#toStdList">toStdList</a>() and <a href="qvector.html#fromStdVector">QVector::fromStdVector</a>().</p>
<a name="//apple_ref/cpp/clm/QList/fromVector"></a>
<h3 class="fn"><a name="fromVector"></a>QList<T> QList::fromVector ( const <a href="qvector.html">QVector</a><T> & <i>vector</i> ) <tt> [static]</tt></h3>
<p>Returns a <a href="qlist.html">QList</a> object with the data contained in <i>vector</i>.</p>
<p>Example:</p>
<pre> QVector<double> vect;
vect << 20.0 << 30.0 << 40.0 << 50.0;
QList<double> list = QVector<T>::fromVector(vect);
<span class="comment"> // list: [20.0, 30.0, 40.0, 50.0]</span></pre>
<p>See also <a href="qlist.html#fromSet">fromSet</a>(), <a href="qlist.html#toVector">toVector</a>(), and <a href="qvector.html#toList">QVector::toList</a>().</p>
<a name="//apple_ref/cpp/instm/QList/front"></a>
<h3 class="fn"><a name="front"></a>T & QList::front ()</h3>
<p>This function is provided for STL compatibility. It is equivalent to <a href="qlist.html#first">first</a>(). The list must not be empty. If the list can be empty, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<h3 class="fn"><a name="front-2"></a>const T & QList::front () const</h3>
<p>This is an overloaded function.</p>
<a name="//apple_ref/cpp/instm/QList/indexOf"></a>
<h3 class="fn"><a name="indexOf"></a>int QList::indexOf ( const T & <i>value</i>, int <i>from</i> = 0 ) const</h3>
<p>Returns the index position of the first occurrence of <i>value</i> in the list, searching forward from index position <i>from</i>. Returns -1 if no item matched.</p>
<p>Example:</p>
<pre> QList<QString> list;
list << "A" << "B" << "C" << "B" << "A";
list.indexOf("B"); <span class="comment">// returns 1</span>
list.indexOf("B", 1); <span class="comment">// returns 1</span>
list.indexOf("B", 2); <span class="comment">// returns 3</span>
list.indexOf("X"); <span class="comment">// returns -1</span></pre>
<p>This function requires the value type to have an implementation of <tt>operator==()</tt>.</p>
<p>Note that <a href="qlist.html">QList</a> uses 0-based indexes, just like C++ arrays. Negative indexes are not supported with the exception of the value mentioned above.</p>
<p>See also <a href="qlist.html#lastIndexOf">lastIndexOf</a>() and <a href="qlist.html#contains">contains</a>().</p>
<a name="//apple_ref/cpp/instm/QList/insert"></a>
<h3 class="fn"><a name="insert"></a>void QList::insert ( int <i>i</i>, const T & <i>value</i> )</h3>
<p>Inserts <i>value</i> at index position <i>i</i> in the list. If <i>i</i> is 0, the value is prepended to the list. If <i>i</i> is <a href="qlist.html#size">size</a>(), the value is appended to the list.</p>
<p>Example:</p>
<pre> QList<QString> list;
list << "alpha" << "beta" << "delta";
list.insert(2, "gamma");
<span class="comment"> // list: ["alpha", "beta", "gamma", "delta"]</span></pre>
<p>See also <a href="qlist.html#append">append</a>(), <a href="qlist.html#prepend">prepend</a>(), <a href="qlist.html#replace">replace</a>(), and <a href="qlist.html#removeAt">removeAt</a>().</p>
<h3 class="fn"><a name="insert-2"></a><a href="qlist-iterator.html">iterator</a> QList::insert ( <a href="qlist-iterator.html">iterator</a> <i>before</i>, const T & <i>value</i> )</h3>
<p>This is an overloaded function.</p>
<p>Inserts <i>value</i> in front of the item pointed to by the iterator <i>before</i>. Returns an iterator pointing at the inserted item. Note that the iterator passed to the function will be invalid after the call; the returned iterator should be used instead.</p>
<a name="//apple_ref/cpp/instm/QList/isEmpty"></a>
<h3 class="fn"><a name="isEmpty"></a>bool QList::isEmpty () const</h3>
<p>Returns true if the list contains no items; otherwise returns false.</p>
<p>See also <a href="qlist.html#size">size</a>().</p>
<a name="//apple_ref/cpp/instm/QList/last"></a>
<h3 class="fn"><a name="last"></a>T & QList::last ()</h3>
<p>Returns a reference to the last item in the list. The list must not be empty. If the list can be empty, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<p>See also <a href="qlist.html#first">first</a>() and <a href="qlist.html#isEmpty">isEmpty</a>().</p>
<h3 class="fn"><a name="last-2"></a>const T & QList::last () const</h3>
<p>This is an overloaded function.</p>
<a name="//apple_ref/cpp/instm/QList/lastIndexOf"></a>
<h3 class="fn"><a name="lastIndexOf"></a>int QList::lastIndexOf ( const T & <i>value</i>, int <i>from</i> = -1 ) const</h3>
<p>Returns the index position of the last occurrence of <i>value</i> in the list, searching backward from index position <i>from</i>. If <i>from</i> is -1 (the default), the search starts at the last item. Returns -1 if no item matched.</p>
<p>Example:</p>
<pre> QList<QString> list;
list << "A" << "B" << "C" << "B" << "A";
list.lastIndexOf("B"); <span class="comment">// returns 3</span>
list.lastIndexOf("B", 3); <span class="comment">// returns 3</span>
list.lastIndexOf("B", 2); <span class="comment">// returns 1</span>
list.lastIndexOf("X"); <span class="comment">// returns -1</span></pre>
<p>This function requires the value type to have an implementation of <tt>operator==()</tt>.</p>
<p>Note that <a href="qlist.html">QList</a> uses 0-based indexes, just like C++ arrays. Negative indexes are not supported with the exception of the value mentioned above.</p>
<p>See also <a href="qlist.html#indexOf">indexOf</a>().</p>
<a name="//apple_ref/cpp/instm/QList/length"></a>
<h3 class="fn"><a name="length"></a>int QList::length () const</h3>
<p>This function is identical to <a href="qlist.html#count">count</a>().</p>
<p>This function was introduced in Qt 4.5.</p>
<p>See also <a href="qlist.html#count">count</a>().</p>
<a name="//apple_ref/cpp/instm/QList/mid"></a>
<h3 class="fn"><a name="mid"></a>QList<T> QList::mid ( int <i>pos</i>, int <i>length</i> = -1 ) const</h3>
<p>Returns a list whose elements are copied from this list, starting at position <i>pos</i>. If <i>length</i> is -1 (the default), all elements from <i>pos</i> are copied; otherwise <i>length</i> elements (or all remaining elements if there are less than <i>length</i> elements) are copied.</p>
<a name="//apple_ref/cpp/instm/QList/move"></a>
<h3 class="fn"><a name="move"></a>void QList::move ( int <i>from</i>, int <i>to</i> )</h3>
<p>Moves the item at index position <i>from</i> to index position <i>to</i>.</p>
<p>Example:</p>
<pre> QList<QString> list;
list << "A" << "B" << "C" << "D" << "E" << "F";
list.move(1, 4);
<span class="comment"> // list: ["A", "C", "D", "E", "B", "F"]</span></pre>
<p>This is the same as insert(<i>to</i>, takeAt(<i>from</i>)).This function assumes that both <i>from</i> and <i>to</i> are at least 0 but less than <a href="qlist.html#size">size</a>(). To avoid failure, test that both <i>from</i> and <i>to</i> are at least 0 and less than <a href="qlist.html#size">size</a>().</p>
<p>See also <a href="qlist.html#swap">swap</a>(), <a href="qlist.html#insert">insert</a>(), and <a href="qlist.html#takeAt">takeAt</a>().</p>
<a name="//apple_ref/cpp/instm/QList/pop_back"></a>
<h3 class="fn"><a name="pop_back"></a>void QList::pop_back ()</h3>
<p>This function is provided for STL compatibility. It is equivalent to <a href="qlist.html#removeLast">removeLast</a>(). The list must not be empty. If the list can be empty, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<a name="//apple_ref/cpp/instm/QList/pop_front"></a>
<h3 class="fn"><a name="pop_front"></a>void QList::pop_front ()</h3>
<p>This function is provided for STL compatibility. It is equivalent to <a href="qlist.html#removeFirst">removeFirst</a>(). The list must not be empty. If the list can be empty, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<a name="//apple_ref/cpp/instm/QList/prepend"></a>
<h3 class="fn"><a name="prepend"></a>void QList::prepend ( const T & <i>value</i> )</h3>
<p>Inserts <i>value</i> at the beginning of the list.</p>
<p>Example:</p>
<pre> QList<QString> list;
list.prepend("one");
list.prepend("two");
list.prepend("three");
<span class="comment"> // list: ["three", "two", "one"]</span></pre>
<p>This is the same as list.insert(0, <i>value</i>).</p>
<p>This operation is usually very fast (<a href="containers.html#constant-time">constant time</a>), because <a href="qlist.html">QList</a> preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list.</p>
<p>See also <a href="qlist.html#append">append</a>() and <a href="qlist.html#insert">insert</a>().</p>
<a name="//apple_ref/cpp/instm/QList/push_back"></a>
<h3 class="fn"><a name="push_back"></a>void QList::push_back ( const T & <i>value</i> )</h3>
<p>This function is provided for STL compatibility. It is equivalent to <a href="qlist.html#append">append</a>(<i>value</i>).</p>
<a name="//apple_ref/cpp/instm/QList/push_front"></a>
<h3 class="fn"><a name="push_front"></a>void QList::push_front ( const T & <i>value</i> )</h3>
<p>This function is provided for STL compatibility. It is equivalent to <a href="qlist.html#prepend">prepend</a>(<i>value</i>).</p>
<a name="//apple_ref/cpp/instm/QList/removeAll"></a>
<h3 class="fn"><a name="removeAll"></a>int QList::removeAll ( const T & <i>value</i> )</h3>
<p>Removes all occurrences of <i>value</i> in the list and returns the number of entries removed.</p>
<p>Example:</p>
<pre> QList<QString> list;
list << "sun" << "cloud" << "sun" << "rain";
list.removeAll("sun");
<span class="comment"> // list: ["cloud", "rain"]</span></pre>
<p>This function requires the value type to have an implementation of <tt>operator==()</tt>.</p>
<p>See also <a href="qlist.html#removeOne">removeOne</a>(), <a href="qlist.html#removeAt">removeAt</a>(), <a href="qlist.html#takeAt">takeAt</a>(), and <a href="qlist.html#replace">replace</a>().</p>
<a name="//apple_ref/cpp/instm/QList/removeAt"></a>
<h3 class="fn"><a name="removeAt"></a>void QList::removeAt ( int <i>i</i> )</h3>
<p>Removes the item at index position <i>i</i>. <i>i</i> must be a valid index position in the list (i.e., 0 <= <i>i</i> < <a href="qlist.html#size">size</a>()).</p>
<p>See also <a href="qlist.html#takeAt">takeAt</a>(), <a href="qlist.html#removeFirst">removeFirst</a>(), <a href="qlist.html#removeLast">removeLast</a>(), and <a href="qlist.html#removeOne">removeOne</a>().</p>
<a name="//apple_ref/cpp/instm/QList/removeFirst"></a>
<h3 class="fn"><a name="removeFirst"></a>void QList::removeFirst ()</h3>
<p>Removes the first item in the list. Calling this function is equivalent to calling removeAt(0). The list must not be empty. If the list can be empty, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<p>See also <a href="qlist.html#removeAt">removeAt</a>() and <a href="qlist.html#takeFirst">takeFirst</a>().</p>
<a name="//apple_ref/cpp/instm/QList/removeLast"></a>
<h3 class="fn"><a name="removeLast"></a>void QList::removeLast ()</h3>
<p>Removes the last item in the list. Calling this function is equivalent to calling removeAt(<a href="qlist.html#size">size</a>() - 1). The list must not be empty. If the list can be empty, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<p>See also <a href="qlist.html#removeAt">removeAt</a>() and <a href="qlist.html#takeLast">takeLast</a>().</p>
<a name="//apple_ref/cpp/instm/QList/removeOne"></a>
<h3 class="fn"><a name="removeOne"></a>bool QList::removeOne ( const T & <i>value</i> )</h3>
<p>Removes the first occurrence of <i>value</i> in the list and returns true on success; otherwise returns false.</p>
<p>Example:</p>
<pre> QList<QString> list;
list << "sun" << "cloud" << "sun" << "rain";
list.removeOne("sun");
<span class="comment"> // list: ["cloud", ,"sun", "rain"]</span></pre>
<p>This function requires the value type to have an implementation of <tt>operator==()</tt>.</p>
<p>This function was introduced in Qt 4.4.</p>
<p>See also <a href="qlist.html#removeAll">removeAll</a>(), <a href="qlist.html#removeAt">removeAt</a>(), <a href="qlist.html#takeAt">takeAt</a>(), and <a href="qlist.html#replace">replace</a>().</p>
<a name="//apple_ref/cpp/instm/QList/replace"></a>
<h3 class="fn"><a name="replace"></a>void QList::replace ( int <i>i</i>, const T & <i>value</i> )</h3>
<p>Replaces the item at index position <i>i</i> with <i>value</i>. <i>i</i> must be a valid index position in the list (i.e., 0 <= <i>i</i> < <a href="qlist.html#size">size</a>()).</p>
<p>See also <a href="qlist.html#operator-5b-5d">operator[]</a>() and <a href="qlist.html#removeAt">removeAt</a>().</p>
<a name="//apple_ref/cpp/instm/QList/size"></a>
<h3 class="fn"><a name="size"></a>int QList::size () const</h3>
<p>Returns the number of items in the list.</p>
<p>See also <a href="qlist.html#isEmpty">isEmpty</a>() and <a href="qlist.html#count">count</a>().</p>
<a name="//apple_ref/cpp/instm/QList/startsWith"></a>
<h3 class="fn"><a name="startsWith"></a>bool QList::startsWith ( const T & <i>value</i> ) const</h3>
<p>Returns true if this list is not empty and its first item is equal to <i>value</i>; otherwise returns false.</p>
<p>This function was introduced in Qt 4.5.</p>
<p>See also <a href="qlist.html#isEmpty">isEmpty</a>() and <a href="qlist.html#contains">contains</a>().</p>
<a name="//apple_ref/cpp/instm/QList/swap"></a>
<h3 class="fn"><a name="swap"></a>void QList::swap ( int <i>i</i>, int <i>j</i> )</h3>
<p>Exchange the item at index position <i>i</i> with the item at index position <i>j</i>. This function assumes that both <i>i</i> and <i>j</i> are at least 0 but less than <a href="qlist.html#size">size</a>(). To avoid failure, test that both <i>i</i> and <i>j</i> are at least 0 and less than <a href="qlist.html#size">size</a>().</p>
<p>Example:</p>
<pre> QList<QString> list;
list << "A" << "B" << "C" << "D" << "E" << "F";
list.swap(1, 4);
<span class="comment"> // list: ["A", "E", "C", "D", "B", "F"]</span></pre>
<p>See also <a href="qlist.html#move">move</a>().</p>
<a name="//apple_ref/cpp/instm/QList/takeAt"></a>
<h3 class="fn"><a name="takeAt"></a>T QList::takeAt ( int <i>i</i> )</h3>
<p>Removes the item at index position <i>i</i> and returns it. <i>i</i> must be a valid index position in the list (i.e., 0 <= <i>i</i> < <a href="qlist.html#size">size</a>()).</p>
<p>If you don't use the return value, <a href="qlist.html#removeAt">removeAt</a>() is more efficient.</p>
<p>See also <a href="qlist.html#removeAt">removeAt</a>(), <a href="qlist.html#takeFirst">takeFirst</a>(), and <a href="qlist.html#takeLast">takeLast</a>().</p>
<a name="//apple_ref/cpp/instm/QList/takeFirst"></a>
<h3 class="fn"><a name="takeFirst"></a>T QList::takeFirst ()</h3>
<p>Removes the first item in the list and returns it. This is the same as takeAt(0). This function assumes the list is not empty. To avoid failure, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<p>This operation is very fast (<a href="containers.html#constant-time">constant time</a>), because <a href="qlist.html">QList</a> preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list.</p>
<p>If you don't use the return value, <a href="qlist.html#removeFirst">removeFirst</a>() is more efficient.</p>
<p>See also <a href="qlist.html#takeLast">takeLast</a>(), <a href="qlist.html#takeAt">takeAt</a>(), and <a href="qlist.html#removeFirst">removeFirst</a>().</p>
<a name="//apple_ref/cpp/instm/QList/takeLast"></a>
<h3 class="fn"><a name="takeLast"></a>T QList::takeLast ()</h3>
<p>Removes the last item in the list and returns it. This is the same as takeAt(<a href="qlist.html#size">size</a>() - 1). This function assumes the list is not empty. To avoid failure, call <a href="qlist.html#isEmpty">isEmpty</a>() before calling this function.</p>
<p>This operation is very fast (<a href="containers.html#constant-time">constant time</a>), because <a href="qlist.html">QList</a> preallocates extra space on both sides of its internal buffer to allow for fast growth at both ends of the list.</p>
<p>If you don't use the return value, <a href="qlist.html#removeLast">removeLast</a>() is more efficient.</p>
<p>See also <a href="qlist.html#takeFirst">takeFirst</a>(), <a href="qlist.html#takeAt">takeAt</a>(), and <a href="qlist.html#removeLast">removeLast</a>().</p>
<a name="//apple_ref/cpp/instm/QList/toSet"></a>
<h3 class="fn"><a name="toSet"></a><a href="qset.html">QSet</a><T> QList::toSet () const</h3>
<p>Returns a <a href="qset.html">QSet</a> object with the data contained in this <a href="qlist.html">QList</a>. Since <a href="qset.html">QSet</a> doesn't allow duplicates, the resulting <a href="qset.html">QSet</a> might be smaller than the original list was.</p>
<p>Example:</p>
<pre> QStringList list;
list << "Julia" << "Mike" << "Mike" << "Julia" << "Julia";
QSet<QString> set = list.toSet();
set.contains("Julia"); <span class="comment">// returns true</span>
set.contains("Mike"); <span class="comment">// returns true</span>
set.size(); <span class="comment">// returns 2</span></pre>
<p>See also <a href="qlist.html#toVector">toVector</a>(), <a href="qlist.html#fromSet">fromSet</a>(), and <a href="qset.html#fromList">QSet::fromList</a>().</p>
<a name="//apple_ref/cpp/instm/QList/toStdList"></a>
<h3 class="fn"><a name="toStdList"></a>std::list<T> QList::toStdList () const</h3>
<p>Returns a std::list object with the data contained in this <a href="qlist.html">QList</a>. Example:</p>
<pre> QList<double> list;
list << 1.2 << 0.5 << 3.14;
std::list<double> stdlist = list.toStdList();</pre>
<p>See also <a href="qlist.html#fromStdList">fromStdList</a>() and <a href="qvector.html#toStdVector">QVector::toStdVector</a>().</p>
<a name="//apple_ref/cpp/instm/QList/toVector"></a>
<h3 class="fn"><a name="toVector"></a><a href="qvector.html">QVector</a><T> QList::toVector () const</h3>
<p>Returns a <a href="qvector.html">QVector</a> object with the data contained in this <a href="qlist.html">QList</a>.</p>
<p>Example:</p>
<pre> QStringList list;
list << "Sven" << "Kim" << "Ola";
QVector<QString> vect = list.toVector();
<span class="comment"> // vect: ["Sven", "Kim", "Ola"]</span></pre>
<p>See also <a href="qlist.html#toSet">toSet</a>(), <a href="qlist.html#fromVector">fromVector</a>(), and <a href="qvector.html#fromList">QVector::fromList</a>().</p>
<a name="//apple_ref/cpp/instm/QList/value"></a>
<h3 class="fn"><a name="value"></a>T QList::value ( int <i>i</i> ) const</h3>
<p>Returns the value at index position <i>i</i> in the list.</p>
<p>If the index <i>i</i> is out of bounds, the function returns a <a href="containers.html#default-constructed-values">default-constructed value</a>. If you are certain that the index is going to be within bounds, you can use <a href="qlist.html#at">at</a>() instead, which is slightly faster.</p>
<p>See also <a href="qlist.html#at">at</a>() and <a href="qlist.html#operator-5b-5d">operator[]</a>().</p>
<h3 class="fn"><a name="value-2"></a>T QList::value ( int <i>i</i>, const T & <i>defaultValue</i> ) const</h3>
<p>This is an overloaded function.</p>
<p>If the index <i>i</i> is out of bounds, the function returns <i>defaultValue</i>.</p>
<a name="//apple_ref/cpp/instm/QList/operator!="></a>
<h3 class="fn"><a name="operator-not-eq"></a>bool QList::operator!= ( const QList<T> & <i>other</i> ) const</h3>
<p>Returns true if <i>other</i> is not equal to this list; otherwise returns false.</p>
<p>Two lists are considered equal if they contain the same values in the same order.</p>
<p>This function requires the value type to have an implementation of <tt>operator==()</tt>.</p>
<p>See also <a href="qlist.html#operator-eq-eq">operator==</a>().</p>
<a name="//apple_ref/cpp/instm/QList/operator+"></a>
<h3 class="fn"><a name="operator-2b"></a>QList<T> QList::operator+ ( const QList<T> & <i>other</i> ) const</h3>
<p>Returns a list that contains all the items in this list followed by all the items in the <i>other</i> list.</p>
<p>See also <a href="qlist.html#operator-2b-eq">operator+=</a>().</p>
<a name="//apple_ref/cpp/instm/QList/operator+="></a>
<h3 class="fn"><a name="operator-2b-eq"></a>QList<T> & QList::operator+= ( const QList<T> & <i>other</i> )</h3>
<p>Appends the items of the <i>other</i> list to this list and returns a reference to this list.</p>
<p>See also <a href="qlist.html#operator-2b">operator+</a>() and <a href="qlist.html#append">append</a>().</p>
<h3 class="fn"><a name="operator-2b-eq-2"></a>QList<T> & QList::operator+= ( const T & <i>value</i> )</h3>
<p>This is an overloaded function.</p>
<p>Appends <i>value</i> to the list.</p>
<p>See also <a href="qlist.html#append">append</a>() and <a href="qlist.html#operator-lt-lt">operator<<</a>().</p>
<a name="//apple_ref/cpp/instm/QList/operator<<"></a>
<h3 class="fn"><a name="operator-lt-lt"></a>QList<T> & QList::operator<< ( const QList<T> & <i>other</i> )</h3>
<p>Appends the items of the <i>other</i> list to this list and returns a reference to this list.</p>
<p>See also <a href="qlist.html#operator-2b-eq">operator+=</a>() and <a href="qlist.html#append">append</a>().</p>
<h3 class="fn"><a name="operator-lt-lt-2"></a>QList<T> & QList::operator<< ( const T & <i>value</i> )</h3>
<p>This is an overloaded function.</p>
<p>Appends <i>value</i> to the list.</p>
<a name="//apple_ref/cpp/instm/QList/operator="></a>
<h3 class="fn"><a name="operator-eq"></a>QList<T> & QList::operator= ( const QList<T> & <i>other</i> )</h3>
<p>Assigns <i>other</i> to this list and returns a reference to this list.</p>
<a name="//apple_ref/cpp/instm/QList/operator=="></a>
<h3 class="fn"><a name="operator-eq-eq"></a>bool QList::operator== ( const QList<T> & <i>other</i> ) const</h3>
<p>Returns true if <i>other</i> is equal to this list; otherwise returns false.</p>
<p>Two lists are considered equal if they contain the same values in the same order.</p>
<p>This function requires the value type to have an implementation of <tt>operator==()</tt>.</p>
<p>See also <a href="qlist.html#operator-not-eq">operator!=</a>().</p>
<a name="//apple_ref/cpp/instm/QList/operator[]"></a>
<h3 class="fn"><a name="operator-5b-5d"></a>T & QList::operator[] ( int <i>i</i> )</h3>
<p>Returns the item at index position <i>i</i> as a modifiable reference. <i>i</i> must be a valid index position in the list (i.e., 0 <= <i>i</i> < <a href="qlist.html#size">size</a>()).</p>
<p>This function is very fast (<a href="containers.html#constant-time">constant time</a>).</p>
<p>See also <a href="qlist.html#at">at</a>() and <a href="qlist.html#value">value</a>().</p>
<h3 class="fn"><a name="operator-5b-5d-2"></a>const T & QList::operator[] ( int <i>i</i> ) const</h3>
<p>This is an overloaded function.</p>
<p>Same as <a href="qlist.html#at">at</a>().</p>
<hr />
<h2>Related Non-Members</h2>
<h3 class="fn"><a name="operator-lt-lt-73"></a><a href="qdatastream.html">QDataStream</a> & operator<< ( <a href="qdatastream.html">QDataStream</a> & <i>out</i>, const QList<T> & <i>list</i> )</h3>
<p>Writes the list <i>list</i> to stream <i>out</i>.</p>
<p>This function requires the value type to implement <tt>operator<<()</tt>.</p>
<p>See also <a href="datastreamformat.html">Format of the QDataStream operators</a>.</p>
<h3 class="fn"><a name="operator-gt-gt-40"></a><a href="qdatastream.html">QDataStream</a> & operator>> ( <a href="qdatastream.html">QDataStream</a> & <i>in</i>, QList<T> & <i>list</i> )</h3>
<p>Reads a list from stream <i>in</i> into <i>list</i>.</p>
<p>This function requires the value type to implement <tt>operator>>()</tt>.</p>
<p>See also <a href="datastreamformat.html">Format of the QDataStream operators</a>.</p>
<p /><address><hr /><div align="center">
<table width="100%" cellspacing="0" border="0"><tr class="address">
<td width="40%" align="left">Copyright © 2010 Nokia Corporation and/or its subsidiary(-ies)</td>
<td width="20%" align="center"><a href="trademarks.html">Trademarks</a></td>
<td width="40%" align="right"><div align="right">Qt 4.6.3</div></td>
</tr></table></div></address></body>
</html>
distrib
>
Mandriva
>
current
>
i586
>
media
>
main-updates
>
by-pkgid
>
8e6051afcdb111a0317a58fb64c2abf5
>
files
>
4425
