I'm trying to handle a bunch of files in a directory. So I used a "List Files" node and a "Table Row To Variable Loop Start" node. But there are some empty files in my input files and they caused trouble at the Loop End. So I added an "Empty Table Swith" and link its first output port to the "Loop End". I wished that the empty table will be sent to the 2nd port and I can get rid of them. Unfortunatly, when the empty table feed to the Empty Table Swith and a red cross showed over its 1st port. And the "Loop End" complains "ERROR Loop End Loop End node in inactive branch not allowed."
Why does it cause trouble, a table with no rows works for me in a loop end.
if the case is no columns either then you can circumvent that by creating a table with table creator and concatenating this with the empty table such that a consistent table structure always reaches the loop end.
I meet a more complex problem. I created a loop in a loop. The outer loop will create empty table sometime. And the inner loop cannot accept the empty table as its input. :( This time the solution of concatenating with an empty table is no longer available.
You could use the Empty table Switch and END if nodes. Put the empty table switch node before the inner loop start and the end if node after the inner loop end node. Connect the inport of the inner loop start node to the top outport of the empty table switch, and the inner loop end node to the top inport of the end if node. And finally connect the bottom of the empty table switch outport directly to the bottom inport of the end if node.
the result of this is that if an empty table is generated then the inner loop is bypassed.