title: How to detect number between underscore ("_")?
body: <p>Sorry first, im not good at Regex but anyone can help me ? i have file that named :</p>
  <blockquote>
  <p>Filename - 01.exe</p>
  <p>Filename - 001.exe</p>
  <p>Filename - 0001.exe</p>
  <p>Filename_01_.exe</p>
  </blockquote>
  <p>I have tried with this Regex</p>
  <pre><code>(?=.*?)\d{1,4}\b
  </code></pre>
  <p>But that just detect 01, 001, 0001 number at Filename - 01.exe, Filename - 001.exe and Filename - 0001.exe, not worked with Filename_01_.exe
  Is my Regex is wrong or there Alternative Regex or Method ?</p>
  <p>Sorry if my english is not well.</p>