\begin{Schunk}
\begin{Sinput}
 oldnames <- colnames(dat)
 oldnames
\end{Sinput}
\begin{Soutput}
 [1] "x"      "y"      "w"      "z"      "y2"     "x2"     "xexp"   "xlog"   "xsqrt"  "xlog.2"
[11] "xlog.3" "xcut"   "rn"     "wn"    
\end{Soutput}
\end{Schunk}
