[R] define subset argument for function lm as variable?

[Joshua Wiley]

Hi Rainer,

You could try:

subs <- expression(dead==FALSE & recTreat==FALSE)

lme(formula, subset = eval(subs))

Not tested, but something along those lines should work.

Cheers,

Josh

On Tue, Aug 21, 2012 at 7:44 AM, Rainer M Krug <r.m.krug at gmail.com> wrote:
> Hi
>
> I want to do a series of linear models, and would like to define the input
> arguments for lm() as variables. I managed easily to define the formula
> arguments in a variable, but I also would like to have the "subset" in a
> variable. My reasoning is, that I have the subset in the results object.
>
> So I wiould like to add a line like:
>
> subs <- dead==FALSE & recTreat==FALSE
>
> which obviously does not work as the expression is evaluated immediately. Is
> is it possible to do what I want to do here, or do I have to go back to use
>
> dat <- subset(dat, dead==FALSE & recTreat==FALSE)
>
> ?
>
>
>
> dat <- loadSPECIES(SPECIES)
> feff <- height~pHarv*year               # fixed effect in the model
> reff <- ~year|plant                     # random effect in the model, where
> year is the
> dat.lme <- lme(
>              fixed = feff,                           # fixed effect in the
> model
>              data  = dat,
>              random = reff,                          # random effect in the
> model
>              correlation = corAR1(form=~year|plant), #
>              subset = dead==FALSE & recTreat==FALSE, #
>              na.action = na.omit
>              )
> dat.lm <- lm(
>             formula =  feff,              # fixed effect in the model
>             data = dat,
>             subset = dead==FALSE & recTreat==FALSE,
>             na.action = na.omit
>             )
>
> Thanks,
>
> Rainer
>
> --
> Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology,
> UCT), Dipl. Phys. (Germany)
>
> Centre of Excellence for Invasion Biology
> Stellenbosch University
> South Africa
>
> Tel :       +33 - (0)9 53 10 27 44
> Cell:       +33 - (0)6 85 62 59 98
> Fax :       +33 - (0)9 58 10 27 44
>
> Fax (D):    +49 - (0)3 21 21 25 22 44
>
> email:      Rainer at krugs.de
>
> Skype:      RMkrug
>
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-- 
Joshua Wiley
Ph.D. Student, Health Psychology
Programmer Analyst II, Statistical Consulting Group
University of California, Los Angeles
https://joshuawiley.com/