On Aug 27, 2014, at 1:11 PM, Gang Chen wrote: > Good point! > > Here is an example: > > library(nlme) > fm <- lme(yield ~ nitro, data=Oats, random=list(Block=pdComSymm(~Variety-1))) >
One problem is that youa re misspelling the function name. > Now the problem I'm facing is that the following part > > pdComSymm(~Variety-1) > > is read in as a string of characters from an external source: > > ranEff <- 'pdComSymm(~Variety-1)' > > The following > > (ranEff1 <- as.formula(ranEff)) > ~Variety - 1 > > is not what I want. Even though > > fm <- lme(yield ~ nitro, data=Oats, random=list(Block=pdCompSymm(ranEff1))) > ranEff <- 'pdCompSymm(~Variety-1)' > tt <- parse(text=ranEff) # Returns an unevaluated expression > fm <- lme(yield ~ nitro, data=Oats, random=list(Block=eval(tt) )) > fm Linear mixed-effects model fit by REML Data: Oats Log-restricted-likelihood: -296.5209 Fixed: yield ~ nitro (Intercept) nitro 81.87222 73.66667 snipped rest of output. -- David > > works, I don't know the 'pdCompSymm' part in advance and would like to > make the process automatic. > > On Wed, Aug 27, 2014 at 3:49 PM, David Winsemius <dwinsem...@comcast.net> > wrote: >> >> On Aug 27, 2014, at 12:44 PM, Gang Chen wrote: >> >>> Thanks for the help! However, I just need to get >>> >>> pdCompSymm(~1 + Age) >> >> That's not a formula in the R sense of the word. You should do a better job >> of posting a use case. Perhaps you want an expression? >> >> -- >> David. >>> >>> without a tilde (~) at the beginning. >>> >>> On Wed, Aug 27, 2014 at 3:34 PM, David Winsemius <dwinsem...@comcast.net> >>> wrote: >>>> >>>> On Aug 27, 2014, at 11:19 AM, Gang Chen wrote: >>>> >>>>> A random effect formulation for R package nlme is read in as a string >>>>> of characters from an input file: >>>>> >>>>> ranEff <- "pdCompSymm(~1+Age)" >>>>> >>>>> I need to convert 'ranEff' to a formula class. However, as shown below: >>>>> >>>>>> as.formula(ranEff) >>>>> ~1 + Age >>>>> >>>>> the "pdCompSymm" is lost in the conversion. Any solutions? >>>> >>>> as.formula(paste("~",ranEff)) >>>> ~pdCompSymm(~1 + Age) >>>> -- >>>> >>>> David Winsemius >>>> Alameda, CA, USA >>>> >> >> David Winsemius >> Alameda, CA, USA >> David Winsemius Alameda, CA, USA ______________________________________________ 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.