Passing a variable to expression section on a rule-based row filter node


I have some filters - one at each line on a table creator - that I want to use in a rule-based row filter. I need to iterate through them so I can create a csv file for each, with its proper results. The values I have to filter come from another table creator and each filter comes in a variable form, within a loop.

The question is: how can I use the filter that comes in a form of a variable, to use it on the Expression section of a rule-based row filter node? I could not find an entry point for this on the node, using a variable.

Here is the example of the flow:


Also, the flow is attached here.

rule based row filter loop.knar.knwf (17.8 KB)


I have solved this problem. It’s probably not the most elegant solution, but it works. rule based row filter loop 1_solution.knwf (55.7 KB)

Hi there @gcfleury,

control rules with filter flow variable.


In case you want to apply multiple rules at once you would need to have all rules in flow variable collection.


Hello scapuzzi, that’s great. It indeed solves my problem. Thank you so much!!!

Hi ipazin, just one doubt: how can I use this string collection?

I can enter one single string, but I could not find information on how to use this string one.


Great. Can you mark my comment as “solution”. Cheers.

Sure, thank you! Regards

Hi @gcfleury,

that is a sign for flow variable type collection holding string values - kind of “list of flow variables”. If you have a collection column type in your table using Table Row to Variable will create a collection flow variable. See here for more info and example workflow: How to send dynamic email attachments?


Hi @ipazin,

Very good and simple explanation on how to achieve a collection of elements. It worked as expected, I could replace the "Expression"contents section of rule based row filter node as I wanted as well as manipulate the filters as I wish.

Thank you so much!

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