<div dir="ltr">Hi Tal,<div><br></div><div>> <span style="font-family:arial,sans-serif;font-size:14px">That is, say that we have x as a List, how do we go about fetching its attr?</span><br style="font-family:arial,sans-serif;font-size:14px">

<span style="font-family:arial,sans-serif;font-size:14px">> I tried:</span><br style="font-family:arial,sans-serif;font-size:14px"><span style="font-family:arial,sans-serif;font-size:14px">> x[1].attr("type")</span><br style="font-family:arial,sans-serif;font-size:14px">

<span style="font-family:arial,sans-serif;font-size:14px">> x.attr[1]("type")</span><br style="font-family:arial,sans-serif;font-size:14px"><span style="font-family:arial,sans-serif;font-size:14px">> But none seemed to have worked. Any suggestions there?</span></div>

<div><font face="arial, sans-serif"><span style="font-size:14px"><br></span></font></div><div><font face="arial, sans-serif"><span style="font-size:14px">Here is a script to show you how to access them:</span></font></div>

<div><font face="arial, sans-serif"><span style="font-size:14px"><br></span></font></div><div><font face="arial, sans-serif"><span style="font-size:14px">```r</span></font></div><div><font face="arial, sans-serif"><div><span style="font-size:14px">x <- list(a = 1, b = 2, c = list(ca = 3, cb = 4, 5), 6)</span></div>

<div><span style="font-size:14px">attr(x[[1]], "type") = "fun"</span></div><div><span style="font-size:14px">attr(x[[3]][[1]], "type") = "fun"</span></div><div><span style="font-size:14px">x</span></div>

<div><span style="font-size:14px"><br></span></div><div><span style="font-size:14px">library(inline);library(Rcpp)</span></div><div><span style="font-size:14px">f <- cxxfunction(sig=c(Rx="list"), plugin="Rcpp", body='</span></div>

<div><span style="font-size:14px"><span class="" style="white-space:pre">       </span>List x(Rx);</span></div><div><span style="font-size:14px"><span class="" style="white-space:pre">      </span>IntegerVector a(wrap(x[0]));</span></div>

<div><span style="font-size:14px"><span class="" style="white-space:pre">       </span>Rcout << as<std::string>(a.attr("type")) << std::endl;</span></div><div><span style="font-size:14px"><span class="" style="white-space:pre">       </span>List c(wrap(x[2]));</span></div>

<div><span style="font-size:14px"><span class="" style="white-space:pre">       </span>IntegerVector ca(wrap(c[0]));</span></div><div><span style="font-size:14px"><span class="" style="white-space:pre">    </span>Rcout << as<std::string>(ca.attr("type")) << std::endl;</span></div>

<div><span style="font-size:14px"><span class="" style="white-space:pre">       </span>')</span></div><div><span style="font-size:14px">f(x)</span></div><div style="font-size:14px">```<br></div></font></div><div><div><br></div>

</div><div>I hope it helps.</div><div><br></div><div>Wush</div></div>