Hello I’m new to Knime and i’m trying to do some simple tasks and i’m having a hard time figuring out what’s possible with what tools… So basically this is my detailed question : how do i do this in knime: for the first 9 columns in a table, add each column with the column of index (current_column index * 9) and the column of index (current_column index * 9 * 2). I have seen so many ideas for this, from groupby to math formula (multiple columns) to rule engine, i’m not sure if any of these can do what i want specifically because they don’t have a function to get the current_column index or to retrive columns by index, can someone help me out ?

Hi @YazanALJ , one of the problems is that having split the table using something like Table Cropper (which can be used to split by column number), it is tricky to concatenate, or “stack” the sub-tables because you need to ensure they each have the same column names. It would be a lot easier and simpler if the Concatenate node could concatenate table columns positionally but unfortunately that option is not there currently. (I live in hope! :wink: ) As a result you need to do some extra work to fix the column names. I have uploaded a workflow with a variety of possible solutions. There may be other options that I haven’t considered… [image] Split and stack table – takbb Workflow showing a number of ways that a table can be split into subsets of columns and then stacked In these examples, there is a table of 20 rows and 27 colu…

Add columns in Knime with specific indices

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takbb April 16, 2024, 5:37am 7

I just searched for the topic for which I created the above component. You might also be interested in this general method of performing matrix calculations, proposed (earlier in that topic) by @Daniel_Weikert