\begin{Schunk}
\begin{Sinput}
 merge(x = datX, y = datY, by = "ID", all= FALSE, incomparables = "NA")
\end{Sinput}
\begin{Soutput}
   ID cars      fear pets
1 111    6  90.61873    5
2 114    6  94.99807    8
3 115    5 106.76902    6
\end{Soutput}
\end{Schunk}
