Hello all! I'm dealing with a problem and I still can't find a way to solve it. Maybe anyone could give me a hind. Suppose you have a matrix with the following structure, Well Plate Sample Detector Ct 1 1 A a1 3 2 1 A a2 4 3 1 B a3 2 4 1 B a4 3 5 1 C a5 1 6 1 C a6 5 7 2 D a1 4 8 2 D a2 4 9 2 E a3 5 10 2 E a4 6 11 2 F a5 5 12 2 F a6 5 This comes from a sds-raw file, an low density array experiment. I converted this hole matrix into the following structure having in mind, in the next step, a quantile normalization between each plate. For this I used the "subset" command: Detector 1 2 a1 3 4 a2 4 4 a3 2 5 a4 3 6 a5 1 5 a6 5 5 I then normalized the arrays. What I need now is to go back to a matrix similar to the first one (where I have a reference between the normalized value and the sample where it belongs to). My idea was to create the same matrix as the normalized one, but instead of values, with the sampleIDs: Detector 1 2 a1 A D a2 A D a3 B E a4 B E a5 C F a6 C F But at this point, I don't know how to match the values with the sample back. I'm sorry for not providing the R-code, I don't know how to generate these specific matrices. Many thanks in advance, Paul [[alternative HTML version deleted]]