In this subthread, the phrase <i>&quot;0-based &#x2F; 1-based&quot;</i> is for the  word &quot;<i>base</i>&quot; accessing the <i>first element</i> which is <i>semantically</i> equivalent to x[0] in C&#x2F;C++&#x2F;Python&#x2F;etc or x[1] in R Language.  Yes in Mathematica, putting &quot;0&quot; between &quot;[&quot; &quot;]&quot; will get you the reserved &quot;head&quot; but that&#x27;s not how people are talking about &quot;0-based&quot; here.