title: UrlRewriter.net Expression Examples
body: <p>I need some web.config examples for each expression types below :</p>
  
  <p><code>$number</code></p>
  
  <p>The last substring matched by group number number.</p>
  
  <p><code>$&lt;name&gt;</code></p>
  
  <p>The last substring matched by group named name matched by <em>(?&lt; name > )</em>.</p>
  
  <p><code>${property}</code></p>
  
  <p>The value of the property when the expression is evaluated.</p>
  
  <p><code>${transform(value)}</code></p>
  
  <p>The result of calling the transform on the specified value.</p>
  
  <p><code>${map:value}</code></p>
  
  <p>The result of mapping the specified value using the map. Replaced with empty string if no mapping exists.</p>
  
  <p><code>${map:value|default}</code></p>
  
  <p>The result of mapping the specified value using the map. Replaced with the default if no mapping exists. </p>
  
  <p><strong>Sample:</strong></p>
  
  <pre><code>&lt;rewriter&gt;
      &lt;if url="/tags/(.+)" rewrite="/tagcloud.aspx?tag=$1" /&gt;
      &lt;!-- same thing as &lt;rewrite url="/tags/(.+)" to="/tagcloud.aspx?tag=$1" /&gt; --&gt;
  &lt;/rewriter&gt;
  </code></pre>
  
  <p>Thank you very much !</p>