\begin{Schunk}
\begin{Sinput}
 eg <- expand.grid(x = c("a", "b", "c"), 
                    y = c("j", "k"), 
                    z = c(1, 2, 3),
                    stringsAsFactors = FALSE)
 ## str(eg)
 lapply(eg, class)
\end{Sinput}
\begin{Soutput}
$x
[1] "character"

$y
[1] "character"

$z
[1] "numeric"
\end{Soutput}
\end{Schunk}
