I like to use split() to split your data into groups, then run lapply() to use fitdistr on each element of the list.
E.g, df <- data.frame(X = rnorm(500), ID = sample(letters[1:5], 500, TRUE)) temp <- split(df$X, df$ID) lapply(temp, fitdistr, "normal") Though it's just as easy with tapply(): tapply(df$X, df$ID, fitdistr, "normal") Michael On Wed, Nov 30, 2011 at 10:00 AM, Carlos Javier Rincon Rodriguez <cjrinc...@unal.edu.co> wrote: > Hi, > > I have a variable X classified in a lot of groups and I need to run the > [fitdistr] funtion for each group. I tried with the [by] or the [tapply] > funtions because my data is organize in two columns (variable and the > groups), but neither of these command work. If somebody have a tip to help > me up I really appreciate it. > > thanks, > > [[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. > ______________________________________________ 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.