In orange, how do you split a given table at a certain row id? I was thinking of adding another column called "Test / Train" in which a 0 would indicate test and a 1 would indicate train data, and then as I'm collecting data end the train data collection phase and start entering each row with 1 in that column.  Then using select rows widget to select all rows with "Test / Train" = 0 or 1.  However, under PCA, the original columns go away so this wouldn't work!

How then, can I just select all rows with row id > k?  I need this because the past data is supposed to predict a smaller set of future data, so I want to be sure that it works and not just select the test set randomly from the training data (which is an option in Test &amp; Score).
Actually, I can add in a string column and should still be able to do the row selection trick even with PCA.  In the file widget you set that column as text / meta and it shows up in the forward row selection widget.

I think this will work.