i d like to ask a question, sorry for my bad english and my poor knowledge of Knime
I ’ m trying to solve a wf wich allows me to pick the first n (e.g.4) values in a column depending on another column. I post a table to explain better
as you can see, i would like to pick the first 4 rows ( or only the values of the column “Ordine…”) of the column “Itinerario” for each different values. For example i d like to pick the firsts 4 rows of value 33000F, the firsts 4 rows of the value “33000G” etc.
I tried with rank node and top k selector node but it doesn t work. Anyone may help me???
Thanks in advice!!!
i think it s solved with a group loop nodes.
thanks in advice
Hi @Pippobaudo89 ,
Glad to hear you found your own solution. And thank you for sharing it to the public.
While the group loop nodes are spot-on, I just want to caution the use of the top-k selector for this particular case.
The node automatically sorts your “Ordien…” column values either in a descending or an ascending manner. It seems that you didn’t mention anything about sorting, and only cared about “the first 4 rows”. If what you meant was the first 4 rows as they originally appear like you showed in the screenshot, then a more suitable node to replace the top k-selector is the Row Filter Node with the following configuration:
The Group nodes stay as they are.
You might want to revise the outcome of your workflow, so that the “first 4 rows” you get correspond to what you really want - unsorted vs sorted.
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