Loop in loop with "table row to variable loop start": problems accessing flow variables


I want to do a Loop in a Loop. If I understand it correctly, the inner Loop has to be wrapped into a wrapped meta node to make that work (is that correct?). But in my wrapped metanode, some flow variables are inaccessible although they are connected by a flow variable inport into the wrapped metanode. How can this be and how can we solve this?


Hi @Knime_Beginner,
You can configure the WrappedNode Input node, specifying the flow variables available to the nodes within the wrapped metanode. To do this, open the metanode and right-click on the WrappedNode Input node and select configure:

There you can include / exclude the variables you need.

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Note that there is no requirement to put nested loops in a wrapped metanode.

You can simply nest loops in the main workflow (or in any metanode) as long as the assignment of start and end nodes can be determined by the workflow structure (i.e. you don’t have any “breaking” connections leading to two end nodes being parallel or some such…). KNIME will complain if it can’t determine the correct nesting of loop nodes.

This aside, of course the solution by @gab1one to inject variables into the wrapped metanode context should work fine as well.

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Thanks for the answers! @gab1one I was able to Access the flow-variables from within the wrapped metanode now.
@imagejan : I use “Table Row to Variable Loop Starts” and they are parallel. I guess that explains why I needed to wrap the inner Loop in a metanode.

Best regards

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