This was just discussed last week: https://www.stat.math.ethz.ch/pipermail/r-help/2006-January/083812.html
On 1/11/06, Christian Bieli <[EMAIL PROTECTED]> wrote: > Dear R-Helpers > > Given a function like > foo <- function(data,var1,var2,var3) { > f <- formula(paste(var1,'~',paste(var2,var3,sep='+'),sep='')) > linmod <- lm(f) > return(linmod) > } > By typing > foo(mydata,'a','b','c') > I get the result of the linear model a~b+c. > How can I rewrite the function so that the formula can be updated inside > the function, i.e. > foo <- function(data,var1,var2,var3,var4) { > f <- formula(paste(var1,'~',paste(var2,var3,sep='+'),sep='')) > linmod <- lm(f) > return(linmod) > f2 <- update.formula(f,.~.-var3+var4) > } > Like that it won't work because var3 and var4 are characters, but also > with substitute() and eval() I did not manage to get the favoured result. > Can somebody help me out? > Thank you in advance > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html