I find that the str() function is really helpful to understand how an object is structured, and therefore how to extract part(s) of it.
Try for example: str(zz) and it might help you understand why zz$coefficients[2,1] is what you were looking for. HTH Ivan -- Dr. Ivan Calandra TraCEr, laboratory for Traceology and Controlled Experiments MONREPOS Archaeological Research Centre and Museum for Human Behavioural Evolution Schloss Monrepos 56567 Neuwied, Germany +49 (0) 2631 9772-243 https://www.researchgate.net/profile/Ivan_Calandra On February 22, 2019 at 8:50 AM Eric Berger <ericjber...@gmail.com> wrote: > You have some choices > > fitchange$coefficients[2] > > zz$coefficients[2,1] > > Note that class(zz$coefficients) shows that it is a matrix. > > HTH, > Eric > > > On Fri, Feb 22, 2019 at 9:45 AM Sorkin, John <jsor...@som.umaryland.edu> > wrote: > > > I am trying to obtain the coefficients from a regression (performed using > > lm). I would like to get the value for the slope (i.e. estimate) for pre > > from the following regression: > > > > > > fitchange <- lm(post-pre~pre,data=mydata2) > > > > > > I have tried the following without any success: > > > > > > zz <- summary(fitchange)["coefficients"] > > class(zz) > > print(zz) > > zz[[2,1]] > > zz[2,1] > > zz["pre","Estimate"] > > > > > > I clearly don't know how to select elements from the list returned by the > > summary function. > > > > > > A reproducible version of my code follows: > > > > > > mydata2 <-structure(list(pre = c(71.3302299440613, 86.2703384845455, > > 120.941698468568, > > 80.9020778388552, 84.9927752038908, > > 77.9108032451793, 111.007107108483, > > 93.288442414475, 126.097826796255, > > 111.63734644637), > > post = c(45.9294556667686, > > 114.661937978585, 138.501558726477, > > 55.355775963925, 97.7906200355594, > > 71.1008233796004, 149.308274695789, > > 122.828428213951, 143.690814568562, > > 116.607579975539)), class = "data.frame", > > row.names = c(NA, -10L)) > > > > fitchange <- lm(post-pre~pre,data=mydata2) > > zz <- summary(fitchange)["coefficients"] > > class(zz) > > print(zz) > > zz[[2,1]] > > zz[2,1] > > zz["pre","Estimate"] > > > > > > Any help you can offer would be appreciated. > > > > > > > > > > > > > > John David Sorkin M.D., Ph.D. > > Professor of Medicine > > Chief, Biostatistics and Informatics > > University of Maryland School of Medicine Division of Gerontology and > > Geriatric Medicine > > Baltimore VA Medical Center > > 10 North Greene Street > > GRECC (BT/18/GR) > > Baltimore, MD 21201-1524 > > (Phone) 410-605-7119 > > (Fax) 410-605-7913 (Please call phone number above prior to faxing) > > > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > > 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 -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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.
