Hi, Is there a way to apply the diff operator over a large data frame, by groups in a single function?
I have a toy data frame that looks like this: MEASUREMENT BLOCK TRATMENT VALUE1 VALUE2 1 1 T-01 15 1 1 1 T-02 32 2 1 2 T-01 21 5 1 2 T-02 32 6 2 1 T-01 19 5 2 1 T-02 37 2 2 2 T-01 29 3 2 2 T-02 36 6 3 1 T-01 21 21 3 1 T-02 45 22 3 2 T-01 38 32 3 2 T-02 40 31 . . . What I would like to calculate is a dataframe that takes the difference between measurements over the same BLOCK-TRATMENT for VALUE1 and VALUE2 Any one know? Cheers, Cristián Montes [[alternative HTML version deleted]]
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.