Feature Request: List / Set Merge

Good morning,

I frequently work with your very convenient collection nodes and regularly happen to face the need to merge multiple columns containing lists or sets.

To merge regular values into a list I first concatenate the values with comma as a separator and use your node Insert into List — NodePit.

However, merging two existing lists or sets seems not directly possible. Only by ungrouping then via Ungroup – KNIME Hub and doing some additional “tricky data pokery”

Kind regards

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Hi Mike,

Thanks for the feedback. I think you can do what you want with the column aggregator node, if you select the two lists or sets and use either the Append Elements (if you want a list) or Union (if you want a set) aggregations as shown in the attached toy example.

Merging lists.knwf (11.4 KB)

If this doesn’t do what you want do let me know!



That is quite a great idea, thanks Steve! I was searching apparently in the wrong location. Maybe because your nodes are just too convenient :wink:


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I think some of the functionality of the nodes can be achieved that way too - I may have also fallen into the same trap when I wrote them, but I’m glad that I’m not the only KNIME-r to have not used the Column Aggregator node, and that someone else also finds the nodes useful!



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