I think you don't need to write "temp.data$a ~ temp.data$b" just "a ~ b"
On Fri, May 20, 2011 at 11:45 AM, Francesco Nutini <nutini.france...@gmail.com> wrote: > Please forgive me for all these questions Dimitri... > > I'm running these input: > > mylist<-NULL #in order to hold my input > for(i in levels(mydataset$c)) { temp.data<-mydataset [mydataset$c %in% i] > mylist[[i]]<- lm(temp.data$a ~ temp.data$b , data=temp.data) } > > > That's the erros returns > Error in `[.data.frame`(mydataset, niger$site %in% i) : > "undefined columns selected" > > > >> Date: Fri, 20 May 2011 10:01:39 -0400 >> Subject: Re: [R] [r] regression coefficient for different factors >> From: dimitri.liakhovit...@gmail.com >> To: nutini.france...@gmail.com >> CC: rb...@atsu.edu; r-help@r-project.org >> >> First you have to create something (e.g., a list) that holds your output: >> >> mylist<-NULL >> >> Then you loop through the levels of c and run a regression of a onto b >> (no need to include c anymore because c will have zero variance within >> each level of c): >> for(i in levels(c)){ >> temp.data<-mydataset[mydataset$c %in% i] >> mylist[[i]]<-lm(a ~ b, data=temp.data) >> } >> >> Once you are done - you can write another loop (this time across all >> elements of mylist - that will have as many elements as there are >> levels in c) and extract the coefficients. >> Dimitri >> >> >> On Fri, May 20, 2011 at 9:57 AM, Francesco Nutini >> <nutini.france...@gmail.com> wrote: >> > Yes Dimitri that's what I mean! >> > Something like this? >> > >> > for(i in levels(c)) { lm(a ~ b * c , data=mydataset)} >> > >> > And what about to see the output? >> > >> > Thanks! >> > >> >> Date: Fri, 20 May 2011 09:46:08 -0400 >> >> Subject: Re: [R] [r] regression coefficient for different factors >> >> From: dimitri.liakhovit...@gmail.com >> >> To: nutini.france...@gmail.com >> >> CC: rb...@atsu.edu; r-help@r-project.org >> >> >> >> Francesco, do you just want a separate regression for each level of >> >> your factor c? >> >> You could write a loop - looping through levels of c: >> >> >> >> for(i in levels(c)){ >> >> select your data here and write a regression formula >> >> } >> >> >> >> On Fri, May 20, 2011 at 9:39 AM, Francesco Nutini >> >> <nutini.france...@gmail.com> wrote: >> >> > >> >> > Thanks for your reply, >> >> > >> >> > ?summary produce a multiple r2. >> >> > My dataset il similar to this one: >> >> > >> >> >> a b c >> >> >> 1 -1.4805676 0.9729927 x >> >> >> 2 1.5771695 0.2172974 x >> >> >> 3 -0.9567445 0.5205087 x >> >> >> 4 -0.9200052 0.8279428 z >> >> >> 5 -1.9976421 0.9641110 z >> >> >> 6 -0.2722960 0.6318801 y >> >> > >> >> > So, I would like to know the r2 for a~b for every factors levels. >> >> > Off course I can made the regression separately for every factors, >> >> > but >> >> > my dataset have 68 factors... >> >> > >> >> > ---------- >> >> > Francesco Nutini >> >> > PhD student >> >> > CNR-IREA (Institute for Electromagnetic Sensing of the Environment) >> >> > Milano, Italy >> >> > >> >> > > From: rb...@atsu.edu >> >> >> To: nutini.france...@gmail.com; r-help@r-project.org >> >> >> Subject: Re: [R] [r] regression coefficient for different factors >> >> >> Date: Fri, 20 May 2011 08:07:59 -0500 >> >> >> >> >> >> ?summary >> >> >> >> >> >> produces r^2 in 2nd to last line, as in, >> >> >> > set.seed(12); a=rnorm(100); b = runif(100); c = factor(rep(c('No', >> >> >> > 'Yes'),50)); df = data.frame(a,b,c) >> >> >> > head(df) >> >> >> a b c >> >> >> 1 -1.4805676 0.9729927 No >> >> >> 2 1.5771695 0.2172974 Yes >> >> >> 3 -0.9567445 0.5205087 No >> >> >> 4 -0.9200052 0.8279428 Yes >> >> >> 5 -1.9976421 0.9641110 No >> >> >> 6 -0.2722960 0.6318801 Yes >> >> >> > mod = lm(a ~ b*c) >> >> >> > summary(mod) >> >> >> >> >> >> Call: >> >> >> lm(formula = a ~ b * c) >> >> >> >> >> >> Residuals: >> >> >> Min 1Q Median 3Q Max >> >> >> -1.8196 -0.4754 -0.0246 0.5585 2.0941 >> >> >> >> >> >> Coefficients: >> >> >> Estimate Std. Error t value Pr(>|t|) >> >> >> (Intercept) 0.2293 0.2314 0.991 0.324 >> >> >> b -0.4226 0.3885 -1.088 0.280 >> >> >> cYes 0.1578 0.3202 0.493 0.623 >> >> >> b:cYes -0.5878 0.5621 -1.046 0.298 >> >> >> >> >> >> Residual standard error: 0.8455 on 96 degrees of freedom >> >> >> Multiple R-squared: 0.07385, Adjusted R-squared: 0.04491 >> >> >> F-statistic: 2.552 on 3 and 96 DF, p-value: 0.0601 >> >> >> >> >> >> ------------------------------------------ >> >> >> Robert W. Baer, Ph.D. >> >> >> Professor of Physiology >> >> >> Kirksville College of Osteopathic Medicine >> >> >> A. T. Still University of Health Sciences >> >> >> 800 W. Jefferson St. >> >> >> Kirksville, MO 63501 >> >> >> 660-626-2322 >> >> >> FAX 660-626-2965 >> >> >> >> >> >> >> >> >> -------------------------------------------------- >> >> >> From: "Francesco Nutini" <nutini.france...@gmail.com> >> >> >> Sent: Friday, May 20, 2011 4:17 AM >> >> >> To: "[R] help" <r-help@r-project.org> >> >> >> 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. >> >> >> > >> >> > >> >> > [[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. >> >> > >> >> >> >> >> >> >> >> -- >> >> Dimitri Liakhovitski >> >> Ninah Consulting >> >> www.ninah.com >> > >> >> >> >> -- >> Dimitri Liakhovitski >> Ninah Consulting >> www.ninah.com > -- Dimitri Liakhovitski Ninah Consulting www.ninah.com ______________________________________________ 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.