<p class="verinfo" >(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose" ><span class="refname">preg_quote</span>—<span class="dc-title">转义正则表达式字符</span></p><h3 class="title" >说明</h3><p><span class="type" >string</span><span class="methodname"><span >preg_quote</span></span>(<span class="methodparam"><span class="type" >string</span><code class="parameter" >$str</code></span>[,<span class="methodparam"><span class="type" >string</span><code class="parameter" >$delimiter</code><span class="initializer" >=<span ><code >NULL</code></span></span></span>] )</p><p class="para rdfs-comment" ><span class="function"><span >preg_quote()</span></span>需要参数<code class="parameter" >str</code>并向其中 每个正则表达式语法中的字符前增加一个反斜线。 这通常用于你有一些运行时字符串 需要作为正则表达式进行匹配的时候。</p><p class="para" >正则表达式特殊字符有：<em >. \ + * ? [ ^ ] $ ( ) { } = ! < > | : -</em></p><p class="para" >注意<em >/</em>不是正则表达式特殊字符。</p><blockquote class="note" ><p ><span class="note" >Note</span>:</p><p class="para" >注意：<span class="function"><span >preg_quote()</span></span>的应用场景不是用于<span class="function"><a href="http://php.net/manual/zh/function.preg-replace.php" class="function" >preg_replace()</a></span>的 $replacement 字符串参数。</p></blockquote><h3 class="title" >参数</h3><p class="para" ><br/></p><ul class=" list-paddingleft-2"><li><p><code class="parameter" >str</code></p></li><li><p class="para" >输入字符串</p></li><li><p><code class="parameter" >delimiter</code></p></li><li><p class="para" >如果指定了可选参数<code class="parameter" >delimiter</code>，它也会被转义。这通常用于 转义PCRE函数使用的分隔符。<em >/</em>是最常见的分隔符。</p></li></ul><h3 class="title" >返回值</h3><p class="para" >返回转义后的字符串。</p><h3 class="title" >更新日志</h3><p class="para" ><br/></p><table class="doctable informaltable" width="1027"><thead><tr class="firstRow"><th >版本</th><th >说明</th></tr></thead><tbody class="tbody"><tr ><td >5.3.0</td><td >字符<em >-</em>被增加为需要转义的。</td></tr></tbody></table><h3 class="title" >范例</h3><p class="para" ><br/></p><p ><span >Example #1<span class="function"><span >preg_quote()</span></span>示例</span></p><p><code ><span ><span ><?php<br/>$keywords</span><span >=</span><span >'$40forag3/400'</span><span >;<br/></span><span >$keywords</span><span >=</span><span >preg_quote</span><span >(</span><span >$keywords</span><span >,</span><span >'/'</span><span >);<br/>echo</span><span >$keywords</span><span >;</span><span >//返回\$40forag3\/400<br/></span><span >?></span></span></code></p><p class="para" ><br/></p><p ><span >Example #2 将文本中的单词替换为斜体</span></p><p><code ><span ><span ><?php<br/></span><span >//在这个例子中，preg_quote($word)用于保持星号原文涵义，使其不使用正则表达式中的特殊语义。<br/><br/></span><span >$textbody</span><span >=</span><span >"Thisbookis*very*difficulttofind."</span><span >;<br/></span><span >$word</span><span >=</span><span >"*very*"</span><span >;<br/></span><span >$textbody</span><span >=</span><span >preg_replace</span><span >(</span><span >"/"</span><span >.</span><span >preg_quote</span><span >(</span><span >$word</span><span >,</span><span >'/'</span><span >).</span><span >"/"</span><span >,<br/></span><span >"<i>"</span><span >.</span><span >$word</span><span >.</span><span >"</i>"</span><span >,<br/></span><span >$textbody</span><span >);<br/></span><span >?></span></span></code></p><h3 class="title" >注释</h3><blockquote class="note" ><p ><span class="note" >Note</span>:<span class="simpara">此函数可安全用于二进制对象。</span></p></blockquote>