You don't have a variable named pd.memb.i Instead, you need something like: get(paste("pd.memb.", i, sep=""))
The error message you're getting, though, is because your loop syntax is wrong: for(i in 1:3) { do something } Sarah On Sun, Sep 18, 2011 at 12:05 PM, Francesco Sarracino <f.sarrac...@gmail.com> wrote: > Dear all, > > I am a stata user and I am moving my first steps in R. > I am dealing with a silly issue concerning looping over variables. I read > previous posts on similar topics in the R help archive, but I did not find a > solution. > Here is my case: > > I run a simple bivariate linear regression saving the output in objects > called: pd.memb.0, pd.memb.1, pd.memb.2, pd.memb.3 > > pd.memb.0 <- lm(E.fs.memb ~ M.fs.memb, data, subset = (tag2 == 1)) > pd.memb.1 <- lm(E.fs.memb ~ M.fs.memb, data, subset = (M.fs.memb <= > quantile(M.fs.memb, .25) & tag2 == 1)) > pd.memb.2 <- lm(E.fs.memb ~ M.fs.memb, data, subset = (M.fs.memb > > quantile(M.fs.memb, .25) & M.fs.memb <= quantile(M.fs.memb, .75) & tag2 == > 1)) > pd.memb.3 <- lm(E.fs.memb ~ M.fs.memb, data, subset = (M.fs.memb > > quantile(M.fs.memb, .75) & tag2 == 1)) > > Subsequently, I wish to plot my data superimposing a different line for each > regression model. Here I am trying to apply my loop. Looking at the info I > found around, the following code sound to me as correct, but I am wrong. > > plot(M.fs.memb , E.fs.memb) > for(i = 1:3){ > curve(coef(pd.memb.i)[1] + coef(pd.memb.i)[2]*x, add = T, cex = 100, col = > "red") > } > > The plot is plotted, but the curves are not printed and I get the following > error message: > > > Error in coef(pd.memb.i) : > error in evaluating the argument 'object' in selecting a method for > function 'coef'> }Error: unexpected '}' in "}" > > > What am I doing wrong? > Thanks a lot for your help, > f. > > [[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. > -- Sarah Goslee http://www.functionaldiversity.org ______________________________________________ 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.