1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>replace_if</title> 5<link rel="stylesheet" href="../../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../../index.html" title="Chapter 1. Fusion 2.2"> 8<link rel="up" href="../functions.html" title="Functions"> 9<link rel="prev" href="replace.html" title="replace"> 10<link rel="next" href="remove.html" title="remove"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="replace.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../functions.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="remove.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h5 class="title"> 27<a name="fusion.algorithm.transformation.functions.replace_if"></a><a class="link" href="replace_if.html" title="replace_if">replace_if</a> 28</h5></div></div></div> 29<h6> 30<a name="fusion.algorithm.transformation.functions.replace_if.h0"></a> 31 <span class="phrase"><a name="fusion.algorithm.transformation.functions.replace_if.description"></a></span><a class="link" href="replace_if.html#fusion.algorithm.transformation.functions.replace_if.description">Description</a> 32 </h6> 33<p> 34 Replaces each element of a given sequence for which an unary function 35 object evaluates to <code class="computeroutput"><span class="keyword">true</span></code> 36 replaced with a new value. 37 </p> 38<h6> 39<a name="fusion.algorithm.transformation.functions.replace_if.h1"></a> 40 <span class="phrase"><a name="fusion.algorithm.transformation.functions.replace_if.synopsis"></a></span><a class="link" href="replace_if.html#fusion.algorithm.transformation.functions.replace_if.synopsis">Synopsis</a> 41 </h6> 42<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 43 <span class="keyword">typename</span> <span class="identifier">Sequence</span><span class="special">,</span> 44 <span class="keyword">typename</span> <span class="identifier">F</span><span class="special">,</span> 45 <span class="keyword">typename</span> <span class="identifier">T</span><span class="special">></span> 46<span class="keyword">typename</span> <a class="link" href="../metafunctions/replace_if.html" title="replace_if"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">replace_if</span></code></a><span class="special"><</span><span class="identifier">Sequence</span> <span class="keyword">const</span><span class="special">,</span> <span class="identifier">F</span><span class="special">,</span> <span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">replace_if</span><span class="special">(</span> 47 <span class="identifier">Sequence</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">seq</span><span class="special">,</span> <span class="identifier">F</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">new_value</span><span class="special">);</span> 48</pre> 49<div class="table"> 50<a name="fusion.algorithm.transformation.functions.replace_if.t0"></a><p class="title"><b>Table 1.71. Parameters</b></p> 51<div class="table-contents"><table class="table" summary="Parameters"> 52<colgroup> 53<col> 54<col> 55<col> 56</colgroup> 57<thead><tr> 58<th> 59 <p> 60 Parameter 61 </p> 62 </th> 63<th> 64 <p> 65 Requirement 66 </p> 67 </th> 68<th> 69 <p> 70 Description 71 </p> 72 </th> 73</tr></thead> 74<tbody> 75<tr> 76<td> 77 <p> 78 <code class="computeroutput"><span class="identifier">seq</span></code> 79 </p> 80 </td> 81<td> 82 <p> 83 A model of <a class="link" href="../../../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward 84 Sequence</a> 85 </p> 86 </td> 87<td> 88 <p> 89 Operation's argument 90 </p> 91 </td> 92</tr> 93<tr> 94<td> 95 <p> 96 <code class="computeroutput"><span class="identifier">f</span></code> 97 </p> 98 </td> 99<td> 100 <p> 101 A function object for which <code class="computeroutput"><span class="identifier">f</span><span class="special">(</span><span class="identifier">e</span><span class="special">)</span></code> is a valid expression, convertible 102 to <code class="computeroutput"><span class="keyword">bool</span></code>, for each 103 element <code class="computeroutput"><span class="identifier">e</span></code> in 104 <code class="computeroutput"><span class="identifier">seq</span></code> 105 </p> 106 </td> 107<td> 108 <p> 109 Operation's argument 110 </p> 111 </td> 112</tr> 113<tr> 114<td> 115 <p> 116 <code class="computeroutput"><span class="identifier">new_value</span></code> 117 </p> 118 </td> 119<td> 120 <p> 121 Any type 122 </p> 123 </td> 124<td> 125 <p> 126 Replacement value 127 </p> 128 </td> 129</tr> 130</tbody> 131</table></div> 132</div> 133<br class="table-break"><h6> 134<a name="fusion.algorithm.transformation.functions.replace_if.h2"></a> 135 <span class="phrase"><a name="fusion.algorithm.transformation.functions.replace_if.expression_semantics"></a></span><a class="link" href="replace_if.html#fusion.algorithm.transformation.functions.replace_if.expression_semantics">Expression 136 Semantics</a> 137 </h6> 138<pre class="programlisting"><a class="link" href="replace_if.html" title="replace_if"><code class="computeroutput"><span class="identifier">replace_if</span></code></a><span class="special">(</span><span class="identifier">seq</span><span class="special">,</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">new_value</span><span class="special">);</span> 139</pre> 140<p> 141 <span class="bold"><strong>Return type</strong></span>: A model of <a class="link" href="../../../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward 142 Sequence</a>. 143 </p> 144<p> 145 <span class="bold"><strong>Semantics</strong></span>: Returns a new sequence with 146 all the elements of <code class="computeroutput"><span class="identifier">seq</span></code>, 147 with <code class="computeroutput"><span class="identifier">new_value</span></code> assigned 148 to each element for which <code class="computeroutput"><span class="identifier">f</span></code> 149 evaluates to <code class="computeroutput"><span class="keyword">true</span></code>. 150 </p> 151<h6> 152<a name="fusion.algorithm.transformation.functions.replace_if.h3"></a> 153 <span class="phrase"><a name="fusion.algorithm.transformation.functions.replace_if.complexity"></a></span><a class="link" href="replace_if.html#fusion.algorithm.transformation.functions.replace_if.complexity">Complexity</a> 154 </h6> 155<p> 156 Constant. Returns a view which is lazily evaluated. 157 </p> 158<h6> 159<a name="fusion.algorithm.transformation.functions.replace_if.h4"></a> 160 <span class="phrase"><a name="fusion.algorithm.transformation.functions.replace_if.header"></a></span><a class="link" href="replace_if.html#fusion.algorithm.transformation.functions.replace_if.header">Header</a> 161 </h6> 162<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">algorithm</span><span class="special">/</span><span class="identifier">transformation</span><span class="special">/</span><span class="identifier">replace_if</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 163<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">replace_if</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 164</pre> 165<h6> 166<a name="fusion.algorithm.transformation.functions.replace_if.h5"></a> 167 <span class="phrase"><a name="fusion.algorithm.transformation.functions.replace_if.example"></a></span><a class="link" href="replace_if.html#fusion.algorithm.transformation.functions.replace_if.example">Example</a> 168 </h6> 169<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">odd</span> 170<span class="special">{</span> 171 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">></span> 172 <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">T</span> <span class="identifier">t</span><span class="special">)</span> <span class="keyword">const</span> 173 <span class="special">{</span> 174 <span class="keyword">return</span> <span class="identifier">t</span> <span class="special">%</span> <span class="number">2</span><span class="special">;</span> 175 <span class="special">}</span> 176<span class="special">};</span> 177<span class="special">...</span> 178<span class="identifier">assert</span><span class="special">(</span><a class="link" href="replace_if.html" title="replace_if"><code class="computeroutput"><span class="identifier">replace_if</span></code></a><span class="special">(</span><a class="link" href="../../../container/generation/functions/make_vector.html" title="make_vector"><code class="computeroutput"><span class="identifier">make_vector</span></code></a><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="number">2</span><span class="special">),</span> <span class="identifier">odd</span><span class="special">(),</span> <span class="number">3</span><span class="special">)</span> <span class="special">==</span> <a class="link" href="../../../container/generation/functions/make_vector.html" title="make_vector"><code class="computeroutput"><span class="identifier">make_vector</span></code></a><span class="special">(</span><span class="number">3</span><span class="special">,</span><span class="number">2</span><span class="special">));</span> 179</pre> 180</div> 181<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 182<td align="left"></td> 183<td align="right"><div class="copyright-footer">Copyright © 2001-2006, 2011, 2012 Joel de Guzman, 184 Dan Marsden, Tobias Schwinger<p> 185 Distributed under the Boost Software License, Version 1.0. (See accompanying 186 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>) 187 </p> 188</div></td> 189</tr></table> 190<hr> 191<div class="spirit-nav"> 192<a accesskey="p" href="replace.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../functions.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="remove.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 193</div> 194</body> 195</html> 196
