1<?xml version="1.0" encoding="utf-8" ?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 4<head> 5<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 6<meta name="generator" content="Docutils 0.7: http://docutils.sourceforge.net/" /> 7<title>The MPL Reference Manual: replace_if</title> 8<link rel="stylesheet" href="../style.css" type="text/css" /> 9</head> 10<body class="docframe refmanual"> 11<table class="header"><tr class="header"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./replace.html" class="navigation-link">Prev</a> <a href="./remove.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./replace.html" class="navigation-link">Back</a> <a href="./remove.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./transformation-algorithms.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> 12<td class="header-group page-location"><a href="../refmanual.html" class="navigation-link">Front Page</a> / <a href="./algorithms.html" class="navigation-link">Algorithms</a> / <a href="./transformation-algorithms.html" class="navigation-link">Transformation Algorithms</a> / <a href="./replace-if.html" class="navigation-link">replace_if</a></td> 13</tr></table><div class="header-separator"></div> 14<div class="section" id="replace-if"> 15<h1><a class="toc-backref" href="./transformation-algorithms.html#id1490">replace_if</a></h1> 16<div class="section" id="id651"> 17<h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> 18<pre class="literal-block"> 19template< 20 typename Sequence 21 , typename Pred 22 , typename NewType 23 , typename In = <em>unspecified</em> 24 > 25struct <a href="./replace-if.html" class="identifier">replace_if</a> 26{ 27 typedef <em>unspecified</em> type; 28}; 29</pre> 30</div> 31<div class="section" id="id652"> 32<h3><a class="subsection-title" href="#description" name="description">Description</a></h3> 33<p>Returns a copy of the original sequence where every type that satisfies 34the predicate <tt class="literal"><span class="pre">Pred</span></tt> has been replaced with <tt class="literal"><span class="pre">NewType</span></tt>.</p> 35<p>[<em>Note:</em> This wording applies to a no-inserter version(s) of the algorithm. See the 36<cite>Expression semantics</cite> subsection for a precise specification of the algorithm's 37details in all cases — <em>end note</em>]</p> 38</div> 39<div class="section" id="id653"> 40<h3><a class="subsection-title" href="#header" name="header">Header</a></h3> 41<pre class="literal-block"> 42#include <<a href="../../../../boost/mpl/replace_if.hpp" class="header">boost/mpl/replace_if.hpp</a>> 43</pre> 44</div> 45<div class="section" id="id654"> 46<h3><a class="subsection-title" href="#model-of" name="model-of">Model of</a></h3> 47<p><a class="reference internal" href="./reversible-algorithm.html">Reversible Algorithm</a></p> 48</div> 49<div class="section" id="id655"> 50<h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> 51<table border="1" class="docutils table"> 52<colgroup> 53<col width="19%" /> 54<col width="43%" /> 55<col width="38%" /> 56</colgroup> 57<thead valign="bottom"> 58<tr><th class="head">Parameter</th> 59<th class="head">Requirement</th> 60<th class="head">Description</th> 61</tr> 62</thead> 63<tbody valign="top"> 64<tr><td><tt class="literal"><span class="pre">Sequence</span></tt></td> 65<td><a class="reference internal" href="./forward-sequence.html">Forward Sequence</a></td> 66<td>An original sequence.</td> 67</tr> 68<tr><td><tt class="literal"><span class="pre">Pred</span></tt></td> 69<td>Unary <a class="reference internal" href="./lambda-expression.html">Lambda Expression</a></td> 70<td>A replacement condition.</td> 71</tr> 72<tr><td><tt class="literal"><span class="pre">NewType</span></tt></td> 73<td>Any type</td> 74<td>A type to replace with.</td> 75</tr> 76<tr><td><tt class="literal"><span class="pre">In</span></tt></td> 77<td><a class="reference internal" href="./inserter.html">Inserter</a></td> 78<td>An inserter.</td> 79</tr> 80</tbody> 81</table> 82</div> 83<div class="section" id="id656"> 84<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> 85<p>The semantics of an expression are defined only 86where they differ from, or are not defined in <a class="reference internal" href="./reversible-algorithm.html">Reversible Algorithm</a>.</p> 87<p>For any <a class="reference internal" href="./forward-sequence.html">Forward Sequence</a> <tt class="literal"><span class="pre">s</span></tt>, an unary <a class="reference internal" href="./lambda-expression.html">Lambda Expression</a> <tt class="literal"><span class="pre">pred</span></tt>, 88an <a class="reference internal" href="./inserter.html">Inserter</a> <tt class="literal"><span class="pre">in</span></tt>, and arbitrary type <tt class="literal"><span class="pre">x</span></tt>:</p> 89<pre class="literal-block"> 90typedef <a href="./replace-if.html" class="identifier">replace_if</a><s,pred,x,in>::type r; 91</pre> 92<table class="docutils field-list" frame="void" rules="none"> 93<col class="field-name" /> 94<col class="field-body" /> 95<tbody valign="top"> 96<tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first">A type.</p> 97</td> 98</tr> 99<tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Equivalent to</p> 100<pre class="last literal-block"> 101typedef <a href="./lambda.html" class="identifier">lambda</a><pred>::type p; 102typedef <a href="./transform.html" class="identifier">transform</a>< s, <a href="./if.html" class="identifier">if_</a>< apply_wrap1<p,<a href="./placeholders.html" class="identifier">_1</a>>,x,<a href="./placeholders.html" class="identifier">_1</a>>, in >::type r; 103</pre> 104</td> 105</tr> 106</tbody> 107</table> 108</div> 109<div class="section" id="id657"> 110<h3><a class="subsection-title" href="#complexity" name="complexity">Complexity</a></h3> 111<p>Linear. Performs exactly <tt class="literal"><span class="pre"><a href="./size.html" class="identifier">size</a><s>::value</span></tt> applications of <tt class="literal"><span class="pre">pred</span></tt>, and at most 112<tt class="literal"><span class="pre"><a href="./size.html" class="identifier">size</a><s>::value</span></tt> insertions.</p> 113</div> 114<div class="section" id="id658"> 115<h3><a class="subsection-title" href="#example" name="example">Example</a></h3> 116<pre class="literal-block"> 117typedef <a href="./vector-c.html" class="identifier">vector_c</a><int,1,4,5,2,7,5,3,5> numbers; 118typedef <a href="./vector-c.html" class="identifier">vector_c</a><int,1,4,0,2,0,0,3,0> expected; 119typedef <a href="./replace-if.html" class="identifier">replace_if</a>< numbers, <a href="./greater.html" class="identifier">greater</a><_,<a href="./int.html" class="identifier">int_</a><4> >, <a href="./int.html" class="identifier">int_</a><0> >::type result; 120 121<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( <a href="./equal.html" class="identifier">equal</a>< result,expected, <a href="./equal-to.html" class="identifier">equal_to</a><_,_> > )); 122</pre> 123</div> 124<div class="section" id="id659"> 125<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> 126<p><a class="reference internal" href="./transformation-algorithms.html">Transformation Algorithms</a>, <a class="reference internal" href="./reversible-algorithm.html">Reversible Algorithm</a>, <a class="reference internal" href="./reverse-replace-if.html">reverse_replace_if</a>, <a class="reference internal" href="./replace.html">replace</a>, <a class="reference internal" href="./remove-if.html">remove_if</a>, <a class="reference internal" href="./transform.html">transform</a></p> 127<!-- Algorithms/Transformation Algorithms//remove |60 --> 128</div> 129</div> 130 131<div class="footer-separator"></div> 132<table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./replace.html" class="navigation-link">Prev</a> <a href="./remove.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./replace.html" class="navigation-link">Back</a> <a href="./remove.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./transformation-algorithms.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> 133<td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> 134Distributed under the Boost Software License, Version 1.0. (See accompanying 135file LICENSE_1_0.txt or copy at <a class="reference external" href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</div></td></tr></table></body> 136</html> 137