Hello,
I have a dataframe with several hundred variables. I would like to
explore updates of some baseline lme fit by including each of some
subset of these variables, one at a time. For various reasons it is
inconvenient to rely on the positions of the numbered columns in the
dataframe. Here is what I want to do:
mod.baseline<-lme(fixed=foo,data=dat,random=bar)
for(thisvar in vars){
<collect stuff from update(mod.baseline, ~ . ~ + thisvar)>
}
I have tried defining "vars" to be a vector of character strings
giving the names of the variables I want to use, and then using
"as.name(thisvar)" in the formula argument to update(). This
doesn't
work (and might be embarrasingly naive). What does seem to work is
"update(mod.baseline,. ~ . + dat[,which(names(dat)==thisvar)])"
but is not elegant and of only limited use because of the lack of
association with the variable name.
My question is whether there is a better way to do this, either with
"vars" as defined above or through some more clever definition.
Thanks to all for your consideration.
J.R. Lockwood
412-683-2300 x4941
lockwood at rand.org
http://www.rand.org/methodology/stat/members/lockwood/
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"J.R. Lockwood" wrote:> > Hello, > > I have a dataframe with several hundred variables. I would like to > explore updates of some baseline lme fit by including each of some > subset of these variables, one at a time. For various reasons it is > inconvenient to rely on the positions of the numbered columns in the > dataframe. Here is what I want to do: > > mod.baseline<-lme(fixed=foo,data=dat,random=bar) > for(thisvar in vars){ > <collect stuff from update(mod.baseline, ~ . ~ + thisvar)> > } > > I have tried defining "vars" to be a vector of character strings > giving the names of the variables I want to use, and then using > "as.name(thisvar)" in the formula argument to update(). This doesn't > work (and might be embarrasingly naive). What does seem to work is > > "update(mod.baseline,. ~ . + dat[,which(names(dat)==thisvar)])" > > but is not elegant and of only limited use because of the lack of > association with the variable name. > > My question is whether there is a better way to do this, either with > "vars" as defined above or through some more clever definition. > > Thanks to all for your consideration.You are looking for get(). Uwe Ligges -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._