Passing dynamically generated flow column list via Flow Variables to column inclusion list.

This topic is for the concerns relating to flow variables. 


I have been trying to pass the dynamically genarated columns to a groupby node. For this I have used the"row to List" node to create flowVariables of the newly genarated colmns. 

I see that the options for Column inclusion in flow Variable tab of groupby node are array size and the column names. 

Please help me on how to use the flowvariable option to acive inclusion of dynamically generate columns from One2Many node.

Hi ramjeesaradi,

so you want to loop on a column, apply the one2many on it and then use the group by on all columns?

I don't see how this should work, as the groupby needs a specific configuration for each column.


However, what is your desired data output? Maybe we can generate a workaround.

Cheers, Iris

Hi iris,

if I understood correctly, i requested something similar for the groupby node where you could apply a default aggregation type for a certain type of column, I.e. All string columns should be  aggregated as First, all numerical should be Mean etc.

i was under the impression this was promised soon, I.e. for knime 2.10.  :-)




Hi Iris,

That is precisely what I want to do.

I understand that the groupby need specific configuration for each column. If I can pass the newly generated column names as flow variables to the "Inclusion Columns", shich I don't know how, I was hoping I could use the similar logic to column specific config which I will genarate using the Java snippet.

I need to rollup multiple records of an entity to one i.e., after the one2many transformation. So I would use max aggregation for all the newly genarated columns except the target variable. The taget variable doesn't vary within the group hence the first occurance is used for the group.

Thanks, ramjeesaradi

Hi Simon,

you are right. This bug is in the system.

I will forward it to Tobias (The master of Grouping) to answer :-)


Cheers, Iris

Hi Simon and Iris,

yes the feature is in the system with a high priority. However up to now I had no time to implement it so do not expect it for the 2.10 release. Sorry about that.


Thanks Iris,

ps: although you replied to my post, it doesn't seem to show up. It said my post was waiting to be moderated.