Hi, What: I am trying to make a Random Forest Scorer combined with Loop and Variable Importance. Let me explain: I have a big table with 50 columns to run a Regression Random Forest. In order to prepare the Random Forest, first, I am evaluating its Variables Importance. I detect that there are more or less 20 columns that are not relevant and confuse the data, and therefore, its better to delete those columns. I have found out that there are 20 columns by test and fail, and I want to make it automatic. My idea is to make a loop of 50 iterations. In each iteration I will look for the less relevant column in the Variable Importance Node I have created, and the idea is to get that column and delete it for the next iteration. If that works well, in the first iteration will be evaluated 50 columns, in the second the best 49 of the past iteration, in the next will be 48, next 47… until no columns are left. In each iteration I run a Regression Random Forest and score it. Once I have ran all the iterations the output is a table with 50 rows, the column deleted in this iteration, and the scorer. Then I plot it to know where cuts the most confident set up. Problem: After 3 whole days looking for it, I have not been able to delete one column in each iteration. Knime doesn’t allow me to connect a node with the result of the iteration and use it to delete a column in the begining of the loop. In the picture you will see one of the several test I have ran, where I cannot connect those 2 nodes, doesn’t allow me. It doesn’t work with this simple methods, nor using Variables or external tables where I add a new column each iteration. I am stuck. Need help!! Thanks, [Captura]

How to: Loop losing 1 column in each iteration.

Iris May 27, 2020, 8:08pm 2

You can use the Feature Selection loop for this.

This is the Loop Start you would use:

And on the hub you can also find an example workflow:

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