How do you handle repeating steps

KNIME Analytics Platform
1

I have many columns. I want to divide the cells in column 2 by the cells in column 3, than I want to do the same with column 4 and 5 and so on. How can i do this in Knime? I don't want to repeat the instructions for every column pair.

Thanks for help

Best regards

wbart

2

Hi Wbart,

When performing such tasks in KNIME you are mostly interested in row wise execution. Then you could apply a Math Formula node and get a result between two (or more) columns for each row.

For a pairwise column comparison we currently do not have an execution model. For such a specific task you would need to either write a script with R/Java/Python Snippet node or setup the workflow using individual nodes.

Hope it helps.

Best, Daria

3

I haven't tried this but you might be able to achieve what you want without scripting by doing something like this:

  • Transpose the source table so rows become columns and vice versa
  • Use a rule-based row splitter to split the table into two, one half containing the dividend rows (formerly columns) and the other half the divisor rows.
  • Transpose the two tables back again
  • Use Extract Table Spec on each one to get a list of the columns it contains and join these into one table with two columns
  • Use a Table Row to Variable loop to give you the names of one pair of columns each iteration
  • Use Math Formula to divide these two columns

Like I say, I haven't tried this!

4

@Tom: Nice solution!! Worth a try.

5

Thanks. It is so complicated :(