I have got a dataframe with following columns product,date,sales
e.g data
product date sales
A 1/1/2011 100
A 2/1/2011 102
.. ..
B 1/1/2011 50
B 2/1/2011 50
I have done forecasting using one variable but dont know how to do when there are multiple dependent variables I want to plot the time series plot of all products including their forecasted value using the trellis plot