title: How to apply regex after applying lookarounds?
body: <br>
  I have txt files which has data something like this:
  <br> file 1<br>
     
  <pre><code>var field = &quot;123456&quot;;
  </code></pre>
  <p>file 2<br></p>
  <pre><code>var field = abdxg@% &quot;345789&quot;;
  </code></pre>
  <p>So I used regex expression:</p>
  <pre><code>(?&lt;=var fhID).*(?=;)
  </code></pre>
  <p><br>This returns: <code>= &quot;123456&quot;</code> in file 1 and <code>= abdxg@% &quot;345789&quot;</code> in file 2.
  <br>Now, I would like a single regex expression that would be able to extract only digits from the string after matching with lookarounds, i.e after modifying my current regex expression I should get <code>123456</code> in file 1 and <code>345789</code> in file 2.</p>