title: Regex to match number(s) or UUID
body: <p>I need regex which loosely matches UUIDs and numbers. I expect my filename to be formatted like: </p>
  
  <pre><code>results_SOMETHING.csv
  </code></pre>
  
  <p>This something ideally should be numbers (count of how many time a script is run) or a UUID. </p>
  
  <p>This regex is encompasses a huge set of filenames:</p>
  
  <pre><code> ^results_?.*.csv$
  </code></pre>
  
  <p>and this one:</p>
  
  <pre><code> ^results_?[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}.csv$
  </code></pre>
  
  <p>matches only UUIDs. I want a regex whose range is somewhere in between. Mostly I don't want matches like <code>result__123.csv</code>.</p>