Hi, I read about the by() function, but it does not seem to do the job I need. Here is the problem:
Say - I have a data frame, with three columns. The first one contains strings that describe the data points, with repeats (for example, days of a week). The other two contain numbers. Something like that: Day val1 val2 Tue 1 2 Tue 2 8 Tue 3 5 Wed 1 2 Wed 1 8 etc. Now I would like to have a data frame with averages for each week: Day val1 val2 Tue 2 5 Wed 1 5 etc. I now I can do tapply(DF$val2, DF$days, mean) to get the means for val2. But I would like to have a data frame as result (as in reality I have many more columns). Further question: where can I find a good, advanced introduction to R data types? R's help() function just kills my brain, and the tutorials are very limited. My kind regards, January Weiner -- ------------ January Weiner 3 ---------------------+--------------- Division of Bioinformatics, University of Muenster | Schloßplatz 4 (+49)(251)8321634 | D48149 Münster http://www.uni-muenster.de/Biologie.Botanik/ebb/ | Germany ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
