On Mon, Jun 20, 2011 at 1:31 PM, albeam <beam.and...@gmail.com> wrote: > Hi everyone, > > Thank you for the help, I apologize for not "providing commented, minimal, > self-contained, reproducible code." I was looking for some pointers about > how to do this in general, but it would have been helpful for me to post a > specific example. Anyway, after the feedback this is the solution I have > settled on for future reference: > > ## Simple Linear Model Example ## > X <- c(1,2,3,4,5) > user.formula <- Y ~ a + b*X > > param.values <- list(a=1.5, b=3, x=X) > eval(user.formula[[3]], envir = param.values) > > #Output# > [1] 4.5 7.5 10.5 13.5 16.5 > > ## Something a little more complicated ## > X <- c(.01,.1,1,10,25,50,100) > > user.formula <- Y ~ Top - (Top-Bot)/(1+(X/b)^W) > param.values <- list(Top=100, Bot=1, b=.05, W=2, x=X) > > eval(user.formula[[3]], envir = param.values) > > #Output# > [1] 1.039584 4.807692 80.200000 99.753117 99.960416 99.990101 99.997525 > > Thanks again. >
Also try this: > library(gsubfn) > X <- c(.01,.1,1,10,25,50,100) > fo <- Y ~ Top - (Top-Bot)/(1+(X/b)^W) > FUN <- fn$identity(fo[-2]) # drop LHS > # and then in your inner loop: > param.values <- list(Top=100, Bot=1, b=.05, W=2, X=X) > do.call(FUN, param.values) [1] 4.807692 80.200000 99.753117 99.997525 99.999604 99.999901 99.999975 where we note that we only had to create FUN once. -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.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.
