title: R find elements with digits and "," only
body: <p>I have a list like this:</p>
  <pre><code> [1] &quot;IIB&quot;                        &quot;142 min&quot;                    &quot;\nDrama            &quot;        &quot;2,315,883&quot;                 
   [5] &quot;$28.34M&quot;                    &quot;IIB&quot;                        &quot;175 min&quot;                    &quot;\nCrime, Drama            &quot;
   [9] &quot;1,599,110&quot;                  &quot;$134.97M&quot;   
  </code></pre>
  <p>I want to find the indexes of elements with digits and &quot;,&quot; only, that is 4 and 9.</p>
  <p>Any help is appreciated.</p>