R : understanding simplified script with brackets or hooks? : <p>I would like to understand how really works this script :</p>

<p><code>y &lt;- y[keep, , keep.lib.sizes=FALSE]</code></p>

<p>in :
<code>keep &lt;- rowSums(cpm(y)&gt;1) &gt;= 3
y &lt;- y[keep, , keep.lib.sizes=FALSE]</code></p>

<p>I do know <code>d.f[a,b]</code> but I can not find R-doc for <code>d.f[a, ,b]</code>.</p>

<p>I tried "brackets", "hooks", "commas"... :-(</p>

<p>(Sometimes I would prefer that one does not simplifie his R script !)</p>

<p>Thanks in advance.</p>
