clogit needs to spell out formula plus strata, you can try modify the code ... d2=d[,c(mols,'group','Age','strata')] fo<-as.formula(paste(paste('group~','Age',sep=''),'strata(strata)',sep='+')) log.reg<-clogit(fo,data=d2) ...
Weidong On Mon, Nov 7, 2011 at 10:19 AM, 1Rnwb <sbpuro...@gmail.com> wrote: > I would like to know if clogit function can be used as below > clogit(group~., data=dataframe) > > When I try to use in above format it takes a long time, I would appreciate > some pointers to get multiple combinations tested. > > set.seed(100) > d=data.frame(x=rnorm(20)+5, > x1=rnorm(20)+5, > x2=rnorm(20)+5, > x3=rnorm(20)+5, > x4=rnorm(20)+5, > x5=rnorm(20)+5, > x6=rnorm(20)+5, > x7=rnorm(20)+5, > x8=rnorm(20)+5, > group=rep(c(1,2),10), Age=rnorm(20)+35,strata=c(rep(1,10), rep(2,10))) > > nam=names(d)[1:9] > results <- c("Protein", "OR", "p-val") > pc3=combinations(n=length(nam),r=2) > > for (len in 1:dim(pc3)[2]) > { > prs=pc3[len,] > mols=nam[prs] > d2=d[,c(mols,'group','Age','strata')] > log.reg<-clogit(group~.,data=d2) > a = summary(log.reg)$conf.int > z= summary(log.reg)$coefficients[1,4] #ncol in coefficients is 3 * number > of parameters > pval = 2*pnorm(-abs(z)) > res2 = c(paste('IL8+',molecule,sep=''), paste (round(a[1,1],2), " (" , > round(a[1,3],2), " - " , round(a[1,4],2), ")" , sep=""), pval) > results = rbind (results ,res2 ) > } > > Thanks > Sharad > > -- > View this message in context: > http://r.789695.n4.nabble.com/help-with-formula-for-clogit-tp3998967p3998967.html > Sent from the R help mailing list archive at Nabble.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. > ______________________________________________ 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.