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I have a table consisting of about 10k Rows and 250 columns, now I want to choose a number of, say 100, columns at random from this table and can not manage this up to now. I made 100 random numbers with the node Random Data Generator, transposed them and then tried to select the columns with node Reference Column Filter. But I could not get this to work. Can anyone give me a hint?

Maybe this wf random_column_select.knwf (84.3 KB) helps you along with your challenge. I think you where almost there. After the Transpose node, I suggest a Row Sampling node and then Transpose the data â€śbackâ€ť again. I added a Column Splitter node in case you donâ€™t want to sample all of them.

Hi @HansS Hans,
thank you for the fast answer. This works, but I get the problem that the second transpose operation (in my case a 100x10000 Matrix lasts a few minutes (!). The first transpose with a 10000x250 matrix is done in two or three seconds. But I can use this for the time until I get a faster solution.

I made a small adjustment to the wf random_column_select.knwf (89.9 KB) . After the Column Splitter I created a Row Filter node, to filter out just 1 row. So both Transpose nodes should go much faster and is input for the Reference Column Filter.
gr. Hans

Hi @HansS this is much faster now - thank you very much. Iâ€™m doing most of my work in Mathematica, so Iâ€™m not very familiar with KNIME and use it most often to validate the Mathematica results (just for sureâ€¦)