Hi: Here are a few one-liners. Calling your data frame dd,
aggregate(cbind(height, weight, age) ~ sample, data = dd, FUN = mean) sample height weight age 1 A 12.20000 0.5033333 6.000000 2 B 12.75000 0.7150000 4.500000 3 C 11.35250 0.5125000 3.750000 4 D 14.99333 0.6733333 5.333333 With package doBy: library(doBy) summaryBy(height + weight + age ~ sample, data = dd, FUN = mean) sample height.mean weight.mean age.mean 1 A 12.20000 0.5033333 6.000000 2 B 12.75000 0.7150000 4.500000 3 C 11.35250 0.5125000 3.750000 4 D 14.99333 0.6733333 5.333333 With package plyr: library(plyr) ddply(dd, .(sample), colwise(mean, .(height, weight, age))) sample height weight age 1 A 12.20000 0.5033333 6.000000 2 B 12.75000 0.7150000 4.500000 3 C 11.35250 0.5125000 3.750000 4 D 14.99333 0.6733333 5.333333 Dennis On Fri, Mar 11, 2011 at 1:32 AM, Aline Santos <aline...@gmail.com> wrote: > Hello R-helpers: > > I have data like this: > > sample replicate height weight age > A 1.00 12.0 0.64 6.00 > A 2.00 12.2 0.38 6.00 > A 3.00 12.4 0.49 6.00 > B 1.00 12.7 0.65 4.00 > B 2.00 12.8 0.78 5.00 > C 1.00 11.9 0.45 6.00 > C 2.00 11.84 0.44 2.00 > C 3.00 11.43 0.32 3.00 > C 4.00 10.24 0.84 4.00 > D 1.00 14.2 0.54 2.00 > D 2.00 15.67 0.67 7.00 > D 3.00 15.11 0.81 7.00 > > Now, how can I calculate the mean for each condition (heigth, weigth, age) > in each sample, considering the samples have different number of > replicates? > > > The final matrix should look like: > > sample height weight age > A 12.20 0.50 6.00 > B 12.75 0.72 4.50 > C 11.35 0.51 3.75 > D 14.99 0.67 5.33 > > This is a simplified version of my dataset, which consist of 100 samples > (unequally distributed in 530 replicates) for 600 different conditions. > > I appreciate all the help. > > A.S. > > [[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. > [[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.
