title: Use variables in pattern matcher
body: <p>I have the following:</p>
  
  <pre><code>if (mobile.matches("[0-9]{6,20}")) {
     ...
  }
  </code></pre>
  
  <p>But would like to replace the {6,20} with variable values due to them been dynamic in some cases.</p>
  
  <p>I.e.</p>
  
  <pre><code>int minValue = 11;
  int maxValue = 20
  
  if (mobile.matches("[0-9]{minValue,maxValue}")) {
     ...
  }
  </code></pre>
  
  <p>How can I include variables in the Reg Exp?</p>
  
  <p>Thanks</p>