I've searched the forums for this topic, but am new to KNIME and may be expressing the problem poorly...
I have a data file which contains a set of columns A-M which I want to preserve in an output table, plus 40 columns which are 10 groups of 4 e.g.
A | B | C | D ... L | M | N1 | O1 | P1 | Q1 | N2 | O2 | P2 | Q2 ... N10 | O10 | P10 | Q10
I have used a Splitter node to partition the data A-M and then N1-Q10; this works well (although I also want to carry across column A (my key) e.g.
A | N1 | O1 | P1 | Q1 | N2 | O2 | P2 | Q2 ... N10 | O10 | P10 | Q10
I then want to take each row and turn 40 columns x 1 row into 4 columns x 10 rows e.g.
A | N | O | P | Q (1)
A | N | O | P | Q (2)
A | N | O | P | Q (3)
A | N | O | P | Q (10)
So I have 2 questions:
- Can I duplicate a column (A) so that I can carry it into both output ports of the Splitter?
- What's the best way to split 40 columns x 1 row into 4 columns x 10 rows... and add column (A) to each?
My current approach (after the Splitter) is:
- Transpose 40 columns x N rows to N columns x 40 rows
- Chunk Loop Start to split into 10 groups of 4 rows
- Transpose to 4 columns x N rows
- Rename columns (to remove 1, 2 etc.) ending up with N | O | P | Q
- End Loop
The first Transpose is pretty quick (completes in 60-70s) but the Transpose inside the loop achieves 10% in 20 minutes... suggesting someting is very wrong!
I have looked at Column List Loop Start, but can't figure out how to use it for this scenario - it would seem to involved a lot less processing, if I can use it?
I hope that all makes sense?!