HI, May be this helps: set.seed(28) dat1<- setNames(as.data.frame(matrix(sample(1:40,10*5,replace=TRUE),ncol=5)),letters[1:5]) indx<-as.data.frame(combn(names(dat1),2),stringsAsFactors=FALSE) res<-t(sapply(indx,function(x) {x1<-cbind(dat1[x[1]],dat1[x[2]]);summary(lm(x1[,1]~x1[,2]))$coef[,4]})) rownames(res)<-apply(indx,2,paste,collapse="_") colnames(res)[2]<- "Coef1" head(res,3) # (Intercept) Coef1 #a_b 0.39862676 0.8365606 #a_c 0.02427885 0.6094141 #a_d 0.37521423 0.7578723
#permutation indx2<-expand.grid(names(dat1),names(dat1),stringsAsFactors=FALSE) #or indx2<- expand.grid(rep(list(names(dat1)),2),stringsAsFactors=FALSE) indx2New<- indx2[indx2[,1]!=indx2[,2],] res2<-t(sapply(seq_len(nrow(indx2New)),function(i) {x1<- indx2New[i,]; x2<-cbind(dat1[x1[,1]],dat1[x1[,2]]);summary(lm(x2[,1]~x2[,2]))$coef[,4]})) row.names(res2)<-apply(indx2New,1,paste,collapse="_") colnames(res2)<- colnames(res) A.K. Hi everyone, First off just like to say thanks to everyone´s contributions. Up until now, I´ve never had to post as I´ve always found the answers from trawling through the database. I´ve finally managed to stump myself, and although for someone out there, I´m sure the answer to my problem is fairly simple, I, however have spent the whole day infront of my computer struggling. I know I´ll probably get an absolute ribbing for making a basic mistake, or not understanding something fully, but I´m blind to the mistake now after looking so long at it. What I´m looking to do, is formulate a matrix ([28,28]) of p-values produced from running linear regressions of 28 variables against themselves (eg a~b, a~c, a~d.....b~a, b~c etc...), if that makes sense. I´ve managed to get this to work if I just input each variable by hand, but this isn´t going to help when I have to make 20 matrices. My script is as follows; for (j in [1:28]) { ##This section works perfectly, if I don´t try to loop it, I know this wont work at the moment, because I haven´t designated what j is, but I´m showing to highlight what I´m attempting to do. models <- lapply(varlist, function(x) { lm(substitute(ANS ~ i, list(i = as.name(x))), data = con.i) }) abc<- lapply(models, function(f) summary(f)$coefficients[,4]) abc<- do.call(rbind, abc) } I get the following error when I try to loop it... Error in model.frame.default(formula = substitute(j ~ i, list(i = as.name(x))), : variable lengths differ (found for 'ANS') ##ÄNS being my first variable All variables are of the same length, with 21 recordings for each If anyone can suggest a method of looping, or another means or producing ´models´ for each of my 28 variables, without having to do it by hand that would be fantastic. Thanks in advance!! ______________________________________________ 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.