function.preg-replace.html

php的帮助文档,涉及到PHP的案例和基本语法,以及实际应用内容

 <div class="refsect1 changelog">
  <h3 class="title">ChangeLog</h3>
  <p class="para">
   <table class="informaltable">
    <colgroup>

     <thead valign="middle">
      <tr valign="middle">
       <th colspan="1">Version</th>
       <th colspan="1">Description</th>
      </tr>

     </thead>

     <tbody valign="middle" class="tbody">
      <tr valign="middle">
       <td colspan="1" rowspan="1" align="left">5.1.0</td>
       <td colspan="1" rowspan="1" align="left">
        Added the <i><tt class="parameter">count</tt></i>
 parameter
       </td>
      </tr>

      <tr valign="middle">
       <td colspan="1" rowspan="1" align="left">4.0.4</td>
       <td colspan="1" rowspan="1" align="left">
        Added the &#039;$n&#039; form for the <i><tt class="parameter">replacement</tt></i>
 parameter
       </td>
      </tr>

      <tr valign="middle">
       <td colspan="1" rowspan="1" align="left">4.0.2</td>
       <td colspan="1" rowspan="1" align="left">
        Added the <i><tt class="parameter">limit</tt></i>
 parameter
       </td>
      </tr>

     </tbody>
    </colgroup>

   </table>
  </p>
 </div>


 <div class="refsect1 examples">
  <h3 class="title">Examples</h3>
  <p class="para">
   <div class="example">
    <p><b>Example #1 Using backreferences followed by numeric literals</b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$string&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'April&nbsp;15,&nbsp;2003'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$pattern&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'/(\w+)&nbsp;(\d+),&nbsp;(\d+)/i'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$replacement&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'${1}1,$3'</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">preg_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$pattern</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$replacement</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$string</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
April1,2003
</pre></div>
    </pre></div>
   </div>
  </p>
  <p class="para">
   <div class="example">
    <p><b>Example #2 Using indexed arrays with <b>preg_replace()</b></b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$string&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'The&nbsp;quick&nbsp;brown&nbsp;fox&nbsp;jumped&nbsp;over&nbsp;the&nbsp;lazy&nbsp;dog.'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$patterns</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #DD0000">'/quick/'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$patterns</span><span style="color: #007700">[</span><span style="color: #0000BB">1</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #DD0000">'/brown/'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$patterns</span><span style="color: #007700">[</span><span style="color: #0000BB">2</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #DD0000">'/fox/'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$replacements</span><span style="color: #007700">[</span><span style="color: #0000BB">2</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #DD0000">'bear'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$replacements</span><span style="color: #007700">[</span><span style="color: #0000BB">1</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #DD0000">'black'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$replacements</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #DD0000">'slow'</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">preg_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$patterns</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$replacements</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$string</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
The bear black slow jumped over the lazy dog.
</pre></div>
    </pre></div>
    <div class="example-contents"><p>
     By ksorting patterns and replacements, we should get what we wanted.
    </p></div>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />ksort</span><span style="color: #007700">(</span><span style="color: #0000BB">$patterns</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">ksort</span><span style="color: #007700">(</span><span style="color: #0000BB">$replacements</span><span style="color: #007700">);<br />echo&nbsp;</span><span style="color: #0000BB">preg_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$patterns</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$replacements</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$string</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
The slow black bear jumped over the lazy dog.
</pre></div>
    </pre></div>
   </div>
  </p>
  <p class="para">
   <div class="example">
    <p><b>Example #3 Replacing several values</b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$patterns&nbsp;</span><span style="color: #007700">=&nbsp;array&nbsp;(</span><span style="color: #DD0000">'/(19|20)(\d{2})-(\d{1,2})-(\d{1,2})/'</span><span style="color: #007700">,<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #DD0000">'/^\s*{(\w+)}\s*=/'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$replace&nbsp;</span><span style="color: #007700">=&nbsp;array&nbsp;(</span><span style="color: #DD0000">'\3/\4/\1\2'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'$\1&nbsp;='</span><span style="color: #007700">);<br />echo&nbsp;</span><span style="color: #0000BB">preg_replace</span><span style="color: #007700">(</span><span style="color: #0000BB">$patterns</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$replace</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'{startDate}&nbsp;=&nbsp;1999-5-27'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
$startDate = 5/27/1999
</pre></div>
    </pre></div>
   </div>
  </p>
  <p class="para">
   <div class="example">
    <p><b>Example #4 Using the &#039;e&#039; modifier</b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />preg_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">"/(&lt;\/?)(\w+)([^&gt;]*&gt;)/e"</span><span style="color: #007700">,&nbsp;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #DD0000">"'\\1'.strtoupper('\\2').'\\3'"</span><span style="color: #007700">,&nbsp;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$html_body</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>
     This would capitalize all HTML tags in the input text.
    </p></div>
   </div>
  </p>
  <p class="para">
   <div class="example">
    <p><b>Example #5 Strip whitespace</b></p>
    <div class="example-contents"><p>
     This example strips excess whitespace from a string.
    </p></div>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$str&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'foo&nbsp;&nbsp;&nbsp;o'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$str&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">preg_replace</span><span style="color: #007700">(</span><span style="color: #DD0000">'/\s\s+/'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'&nbsp;'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$str</span><span style="color: #007700">);<br /></span><span style="color: #FF8000">//&nbsp;This&nbsp;will&nbsp;be&nbsp;'foo&nbsp;o'&nbsp;now<br /></span><span style="color: #007700">echo&nbsp;</span><span style="color: #0000BB">$str</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>
  <p class="para">
   <div class="example">
    <p><b>Example #6 Using the <i><tt class="parameter">count</tt></i>
 parameter</b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$count&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">;<br /><br />echo&nbsp;</span><span style="color: #0000BB">preg_replace</span><span style="color: #007700">(array(</span><span style="color: #DD0000">'/\d/'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'/\s/'</span><span style="color: #007700">),&nbsp;</span><span style="color: #DD0000">'*'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'xp&nbsp;4&nbsp;to'</span><span style="color: #007700">,&nbsp;-</span><span style="color: #0000BB">1&nbsp;</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$count</span><span style="color: #007700">);<br />echo&nbsp;</span><span style="color: #0000BB">$count</span><span style="color: #007700">;&nbsp;</span><span style="color: #FF8000">//3<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
xp***to
3
</pre></div>
    </pre></div>
   </div>
  </p>
 </div>


 <div class="refsect1 notes">
  <h3 class="title">Notes</h3>
  <blockquote><p><b class="note">Note</b>: 
   
    When using arrays with <i><tt class="parameter">pattern</tt></i>
 and
    <i><tt class="parameter">replacement</tt></i>
, the keys are processed in the order
    they appear in the array. This is <em class="emphasis">not necessarily</em> the
    same as the numerical index order. If you use indexes to identify which
    <i><tt class="parameter">pattern</tt></i>
 should be replaced by which
    <i><tt class="parameter">replacement</tt></i>
, you should perform a
    <a href="function.ksort.html" class="function">ksort()</a> on each array prior to calling
    <b>preg_replace()</b>.
   <br />
  </p></blockquote>
 </div>


 <div class="refsect1 seealso">
  <h3 class="title">See Also</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><a href="function.preg-match.html" class="function" rel="rdfs-seeAlso">preg_match()</a></li>
    <li class="member"><a href="function.preg-replace-callback.html" class="function" rel="rdfs-seeAlso">preg_replace_callback()</a></li>
    <li class="member"><a href="function.preg-split.html" class="function" rel="rdfs-seeAlso">preg_split()</a></li>
   </ul>
  </p>
 </div>

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