Variable stack, loop problem

[ChineS]

Hi everyone,

I hope this topic is not a repetition of an existing thread. I need to run the following workflow.

Here I need to process some data within a recursive loop using rows (one by one) from another table, so I need to use a chunk loop, but the problem with variables occurs. If I connect the variable ports of the Recursive Loop Start and the Chunk Loop Start, the latter does not change the rows anymore so the loop process always the same table. If I connect them the other way, I get the error that the Recursive Loop End is not connected with the corresponding Loop Start node.

Could someone please explain once and for all how to connect somehow two loops or to use properly recursive loops in general?

Please contact me if you need some more information or solutions

Have a nice time!

Silvia

[mlauber71]

@ChineS you can not just mix loops. You will have to use a correct ‘wireing’. You could read more about loops here:

How to include file CSV Writer in a loop?

Hi @braunnz and welcome to the KNIME community forum, You can find your answer here (and learn more about loops in KNIME): https://blog.statinfer.com/which-loop-is-the-right-one-for-me/ And here you can learn more about making use of flow variables in KNIME: https://blog.statinfer.com/knime-spirits-at-your-service/

A meta collection about Loops, Switches, Paths and Flow Variables in KNIME...

If you create an example that does represent your problem it might be easier to make some suggestions.

[ipazin]

Hello @ChineS,

think in this case you might find Recursive Loop Start (2 ports) and Recursive Loop End (2 ports) useful. In each iteration you take only first row from table that you now feed to Chunk Loop Start and feed Loop End node without. (You can use Rule-based Row Splitter node for it with rule based on row index.)

Br,
Ivan

[ChineS]

Thanks, that solved completely the problem! This community never delude!