Here's another option using the plyr package: library(plyr) ddply(dat, 'f', function(d) coef(lm(A ~ B, data = d)))
Dennis On Fri, May 20, 2011 at 7:34 PM, <bill.venab...@csiro.au> wrote: > You have received suggestions about this already, but you may want to > consider something like this as an alternative: > >> require(english) >> lev <- as.character(as.english(0:9)) >> dat <- data.frame(f = factor(sample(lev, 500, > + rep=TRUE), levels = lev), > + B = rnorm(500)) >> dat <- within(dat, A <- 2 + 3*B + rnorm(B)) >> >> ### method 1: using a loop >> coefs <- sapply(levels(dat$f), > + function(x) coef(lm(A ~ B, dat, > + subset = f == x))) >> t(coefs) > (Intercept) B > zero 1.967234 2.795218 > one 1.864298 3.048861 > two 1.978757 2.893950 > three 2.035777 2.796963 > four 2.092047 2.826677 > five 2.263936 3.229843 > six 1.740911 3.114069 > seven 1.975918 3.090971 > eight 2.064802 3.048225 > nine 2.030697 3.059960 >> >> ### Greg Snow's suggeston - use lmList >> require(nlme) >> coef(lmList(A ~ B | f, dat)) > (Intercept) B > zero 1.967234 2.795218 > one 1.864298 3.048861 > two 1.978757 2.893950 > three 2.035777 2.796963 > four 2.092047 2.826677 > five 2.263936 3.229843 > six 1.740911 3.114069 > seven 1.975918 3.090971 > eight 2.064802 3.048225 > nine 2.030697 3.059960 >> > > Bill Venables > ________________________________________ > From: r-help-boun...@r-project.org [r-help-boun...@r-project.org] On Behalf > Of Francesco Nutini [nutini.france...@gmail.com] > Sent: 20 May 2011 19:17 > To: [R] help > Subject: [R] [r] regression coefficient for different factors > > Dear R-helpers, > > In my dataset I have two continuous variable (A and B) and one factor. > I'm investigating the regression between the two variables usign the command > lm(A ~ B, ...) > but now I want to know the regression coefficient (r2) of A vs. B for every > factors. > I know that I can obtain this information with excel, but the factor have 68 > levels...maybe [r] have a useful command. > > Thanks, > > Francesco Nutini > > [[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. > ______________________________________________ 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.
