search for: plateno

...figure out how to perform calculations on a large dataset (300 000 datapoints). I have already made some code to do this but it is awfully slow. What I want to do is add a new column for each "rep_ " column where I have taken each value and divide it by the mean of all values where "PlateNo" is the same. My data is in the following format: > data PlateNo Well rep_1 rep_2 rep_3 1 A01 1312 963 1172 1 A02 10464 6715 5628 1 A03 3301 3257 3281 1 A04 3895 3350 3496 1 A05 8731 7389 5701 2 A01 7893 6748 5920 2 A02 2912 2385 2586...