Ok, I've modified it as suggested so as to not pass to the global. Thanks for the suggestions, and the link to the interesting reading.
On Fri, Mar 30, 2012 at 12:26 PM, William Dunlap <wdun...@tibco.com> wrote: > I think you will be happier in the long run if you use the approach > Peter suggested. Do not use <<-, remove the calls to rm() > from your function (because they do nothing useful -- all variables > in a function disappear when the function is done), have it return > its local variable 'test' and call it as > test5 <- plotter(5) > > If you treat all variables as globals you will run into trouble. > > Bill Dunlap > Spotfire, TIBCO Software > wdunlap tibco.com > > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > On Behalf > > Of Benjamin Caldwell > > Sent: Friday, March 30, 2012 12:09 PM > > To: Peter Langfelder > > Cc: r-help > > Subject: Re: [R] scalar assignment within a vector within function > > > > Thanks all - ended up going with > > test<<-test > > > > On Thu, Mar 29, 2012 at 4:40 PM, Peter Langfelder < > > peter.langfel...@gmail.com> wrote: > > > > > On Thu, Mar 29, 2012 at 3:49 PM, Benjamin Caldwell > > > <btcaldw...@berkeley.edu> wrote: > > > > Hello, > > > > > > > > I'm trying to create a vector of r^2 values for using a function > which I > > > > will run in a "for" loop. Example: > > > > > > > > per<-rnorm(100,.5,.2)^2 > > > > x<-rnorm(100,10,5) > > > > y<-rnorm(100,20,5) > > > > fr<-data.frame(x,y,per) > > > > > > > > test<-rep(0,9) > > > > > > > > plotter<-function(i){ > > > > temp.i<-fr[fr$per <=(i*.10),] > > > > with(temp.i, plot(x, y, main=(i*.10),)) > > > > mod<-lm(y~x-1,data=temp.i) > > > > r2<-summary(with(temp.i, lm(y~x)))$adj.r.squared > > > > legend("bottomright", legend=signif(r2), col="black") > > > > test[i]<-r2 > > > > print(r2) > > > > abline(mod) > > > > rm(temp.i) > > > > rm(i) > > > > rm(mod) > > > > rm(r2) > > > > } > > > > > > > > test > > > > > > > > Test comes up as the original vector of zeros. I know r2 is created > for a > > > > couple reasons (print works, and they show up on the graphs). Also, > if I > > > > run the function line by line with i assigned a number, test[i] is > > > assigned > > > > as it should be. However, if I call the function, plotter(i), test > is not > > > > modified, although the r^2 prints. > > > > > > > > Mystified. What am I missing? > > > > > > > > > Add the line > > > > > > test > > > > > > to the end of your function; this will cause the function to return > > > the value of the vector test. > > > > > > Then call the function as > > > > > > test = plotter(1) > > > > > > or something. > > > > > > You're missing the fact that in R all function arguments are passed by > > > value (think of them as being copied) and your function assigns a > > > value in a local copy of the vector test. This copy is discarded when > > > the function exits. The global copy is not modified. Of course, when > > > you step through the lines individually (not within a function call), > > > you work with the global test. > > > > > > HTH > > > > > > Peter > > > > > > > [[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.
