Rule based column filter?


I am working on a project where we convert input images with color deconvolution to 3 images and the original. After that we make a histogram of the images. I use a transform to put the histograms in the columns. So with 3 input images I end up with 12 columns with a histogram
I can put them all in an excel sheet. That all works.
Now i am looking for a way to create one excel for every input image. So every excel should have the four histogram columns belonging to the input image.
I am trying the “table row to variable loop start” (with data from before the transform so i have the image names) The image names are also part of the name of the column with the histograms.
There is no Rule based column filter as far a I know. What is the best way to split the columns?

I hope the question is clear.


I have found a solution. I don’t know if anybody can use it but I used the Table Row To Variable Loop Start and with the String Manipulation created the regex in an flow parameter that can be used in the Column filter.


Hi Boudewijn

good to hear that it worked! Not sure if I got your question right, but maybe that workflow would have also given some inspiration:

Alternatively my first guess would have been a sequence of Column Splitter nodes (although that probably wouldn’t have been the cleanest way).


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Hello @Boudewijn,

seems like a good approach to me. If you want others to use it/try it out you can share it on KNIME Hub.



It is part of a bigger workflow.I think you will need the context, hope the workflow provides it:


Hi @Boudewijn,

Nice one. I had in mind only to share approach from problem from this topic as this is what other users might be interested in (me included) but seems they like workflow as it has been downloaded 24 times in 3 days :+1:

And for sure I need context as I’m not in Image Processing…


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