1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Property Tree as a Container</title> 6<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../property_tree.html" title="Chapter 31. Boost.PropertyTree"> 10<link rel="prev" href="tutorial.html" title="Five Minute Tutorial"> 11<link rel="next" href="synopsis.html" title="Property Tree Synopsis"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td> 16<td align="center"><a href="../../../index.html">Home</a></td> 17<td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td> 18<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 19<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 20<td align="center"><a href="../../../more/index.htm">More</a></td> 21</tr></table> 22<hr> 23<div class="spirit-nav"> 24<a accesskey="p" href="tutorial.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../property_tree.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="synopsis.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="section"> 27<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 28<a name="property_tree.container"></a><a class="link" href="container.html" title="Property Tree as a Container">Property Tree as a Container</a> 29</h2></div></div></div> 30<p> 31 Every property tree node models the ReversibleSequence concept, providing access 32 to its immediate children. This means that iterating over a <code class="computeroutput"><a class="link" href="../boost/property_tree/ptree.html" title="Type definition ptree">ptree</a></code> 33 (which is the same as its root node - every <code class="computeroutput"><a class="link" href="../boost/property_tree/ptree.html" title="Type definition ptree">ptree</a></code> 34 node is also the subtree it starts) iterates only a single level of the hierarchy. 35 There is no way to iterate over the entire tree. 36 </p> 37<p> 38 It is very important to remember that the property sequence is <span class="bold"><strong>not</strong></span> 39 ordered by the key. It preserves the order of insertion. It closely resembles 40 a std::list. Fast access to children by name is provided via a separate lookup 41 structure. Do not attempt to use algorithms that expect an ordered sequence 42 (like binary_search) on a node's children. 43 </p> 44<p> 45 The property tree exposes a second container-like interface, called the associative 46 view. Its iterator type is the nested type assoc_iterator (and its const counterpart 47 const_assoc_iterator). You can get an ordered view of all children by using 48 ordered_begin() and ordered_end(). 49 </p> 50<p> 51 The associative view also provides find() and equal_range() members, which 52 return assoc_iterators, but otherwise have the same semantics as the members 53 of std::map of the same name. 54 </p> 55<p> 56 You can get a normal iterator from an assoc_iterator by using the to_iterator() 57 member function. Converting the other way is not possible. 58 </p> 59</div> 60<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 61<td align="left"></td> 62<td align="right"><div class="copyright-footer">Copyright © 2008-2010 Marcin Kalicinski<br>Copyright © 2010-2013 Sebastian 63 Redl<p> 64 Distributed under the Boost Software License, Version 1.0. (See accompanying 65 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 66 </p> 67</div></td> 68</tr></table> 69<hr> 70<div class="spirit-nav"> 71<a accesskey="p" href="tutorial.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../property_tree.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="synopsis.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 72</div> 73</body> 74</html> 75
