please help me with native nodes
Hi there @chezhiyan ,
I don’t see a really easy way to do it. Here is how I got it:
Both approaches use loop. Now chose one you like more
thanks @ipazin… my table has 1m rows… after i started loop it never stopped running i was expecting some kinda rule engine/native node/python script, that runs it faster… knime should think about this, a simple index match in excel taking so much time in knime is bad.
Also is it possible to find the index of the column by min formula and then do a lookup from a column name extracter…? please help
looks perfect can you share the workflow?
…but if your dataset consists of a million rows, it is probably better to do it in chunks.
Here is the workflow:
KNIME_project2.knwf (22.9 KB)
Ooops sorry @chezhiyan it seems I forgot to configure the loop correctly. It also turns out you don’t even need the Column Appender if you configure the Unpivot and GroupBy nodes a bit differently. The best workflow is a perfectly horizontal branchfree workflow
KNIME_project3.knwf (18.2 KB)
approach could be improved a bit but not enough for 1 million rows I afraid.
something is wrong, results are not correct
You say it doesn’t work; do you mean it doesn’t work for the example table in your original post or for your million-row table? On my PC it seems to work fine for the example table. Maybe your million-row table has a combination of different column types that cannot be easily sorted? For example, a mix of string- and numeric columns? That can sometimes happen when importing excel data.
can we do it without sorting? i think that causes an error? is it possible to extract column header seperately? and find column index based on min value and then look up to the table? i think that will work better, but i dont know how to do
@chezhiyan there you go, a solution without sorting.
KNIME_project3.knwf (18.6 KB)
A column index method, as you suggest, may be possible somehow with the Column Expressions node…
Hi all, haven’t compared for speed but here’s one more example to try. More the merry right?
In the event of 2 columns sharing the max value it grabs the left most column name.
Max column.knwf (8.2 KB)
search in a matric
Awesome @Corey, nice opportunity for me to learn about the Column Expression node, that one is still a bit mysterious to me. I was wondering: do we really need the Column Aggregator? Turns out we don’t
Max column.knwf (6.7 KB)
Here is yet another method, one that avoids the scary Column Expressions node…
KNIME_project3.knwf (17.3 KB)
You’re correct! We can just use 2 expressions in the column expressions node if desired.
I had done it with the column aggregator to keep “scripting” to a minimum and because I wonder if it might be faster on large data sets.
I say test both if speed is a concern.
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