Hi Eik, Thanks, that got me on the right track. After looking at how get_all_vars() works, I am using:
all.vars(as.formula(m)) which works great. Thanks again, Josh On Wed, Aug 17, 2011 at 6:14 AM, Eik Vettorazzi <e.vettora...@uke.uni-hamburg.de> wrote: > Hi Josh, > I think, > > m <- lm(mpg ~ factor(cyl)+I(mpg^2), data = mtcars) > nd<-get_all_vars(m,data=mtcars) > > is what you are after. > > cheers. > > Am 17.08.2011 04:27, schrieb Joshua Wiley: >> Hi All, >> >> I am writing a function to predict values based on a model. It works >> fine as long as the formula just uses regular variable names. I am >> having a problem when the variables are wrapped with a function call. >> For example: >> >> m <- lm(mpg ~ factor(cyl), data = mtcars) >> ## I get the column names using >> as.character(attr(terms(m), "variables"))[-1L] >> ## which gives the same column names as in >> # m$model >> >> predict(m, m$model) # returns an error that 'cyl' is not found >> >> Is there an easy way to get just the variable names or a template data >> frame that I can populate with my own values from a model object? My >> best idea right now is to use a regular expression to strip away >> everything before and after (). This would break down for things like >> I(cyl^2), though. >> >> Any ideas or thoughts would be welcome. >> >> Thanks, >> >> Josh >> >> > > -- > Eik Vettorazzi > Institut für Medizinische Biometrie und Epidemiologie > Universitätsklinikum Hamburg-Eppendorf > > Martinistr. 52 > 20246 Hamburg > > T ++49/40/7410-58243 > F ++49/40/7410-57790 > -- Joshua Wiley Ph.D. Student, Health Psychology Programmer Analyst II, ATS Statistical Consulting Group University of California, Los Angeles https://joshuawiley.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.