\begin{Schunk}
\begin{Sinput}
 w1 <- fd[ , "v4", drop = FALSE]
 w1
\end{Sinput}
\begin{Soutput}
               v4
Bill    0.1401390
Joe     0.2091844
Frosty -3.0360898
Mickey -0.4869341
Henry  -1.0878673
\end{Soutput}
\begin{Sinput}
 str(w1)
\end{Sinput}
\begin{Soutput}
'data.frame':	5 obs. of  1 variable:
 $ v4: num  0.14 0.209 -3.036 -0.487 -1.088
\end{Soutput}
\end{Schunk}
