loop with 2 ends ?

I am doing some fancy assay plate processing trickery in knime 2.7.4, but ran into a looping issue.

I loop over the data per plate with a Group Loop Start, then do some magic that includes some math, pivoting and transpose, a variable is edited to form the filename of the resulting csv file (for each plate) and this is stored using the CSV_Writer, after wich the loop ends with a Variable Loop End (connected to the CSV_Writer, as that is its only output port).

So far so good.

But for each plate i also gather some statistical information, one row for each plate/itteration, and i would like to bundle this together, at this time in a separate file.
I thought to do that by connecting a normal Loop End node to concatenate those, but that gives all types of weirdness if you connect 2 loop ends.

I now solved it for now by writing out the statistical information within the loop using the CSV_Writer in append mode, but this makes me a little uncomfortable, and it has the drawback that if i reset the loop and run it again, the statistical data is duplicated in the output file.

If i ever wanted to use both datasets for further processing in this workflow, would there be a way to get them both out from the one loop ?

There is a loop end node with two output ports. Each loop start node can only connect to one loop end node as far as I am aware so you can't use two independant loop ends.

 

The loop end (2 ports) should do what you want though. 

 

"Node at the end of a loop. It is used to mark the end of a workflow loop and collects the intermediate results by row-wise concatenation of the incoming tables. The start of the loop is defined by the loop start node, in which you can define how often the loop should be executed (either fixed or derived from data, e.g. the "group loop start"). All nodes in between are executed that many times."

 

Cheers

 

Sam

 

 

That works, thank you for your sharp observation.