title: regex match set of characters after certain character without including it
body: <p>This is the string I have:</p>
  <pre class="lang-html prettyprint-override"><code>text-center font-weight-bold rounded-0&quot; name=&quot;5af417ac324df4c6&quot; placeholder=&quot;Enter Video URL&quot; aria-des...
  </code></pre>
  <p>I want to match <code>5af417ac324df4c6</code>, more exactly a 16 character long alphanumeric string. In the text there is other patterns that may get selected in the regex but are unwanted and to filter them out I use the parameter that the regex should only match characters after <code>&quot;</code>.</p>
  <pre class="lang-html prettyprint-override"><code>\&quot;[a-z0-9]{16} or &quot;[a-z0-9]{16}
  </code></pre>
  <p>Now comes the problem, if I do so, <code>&quot;</code> also gets selected in the matching strings</p>
  <p>one solution I found: <code>(?&lt;=&quot;)[a-z0-9]{16}</code>, <strong>but <code>(?&lt;</code> is not supported in golang</strong>.</p>
  <p>How can I achieve this</p>