HI, Using the example dataset (Test_data.csv): dat1<- read.csv("Test_data.csv",header=TRUE,sep="\t",row.names=1) indx2<-expand.grid(names(dat1),names(dat1),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]})) dat2<- cbind(indx2New,value=res2[,2]) library(reshape2) res2New<- dcast(dat2,Var1~Var2,value.var="value") row.names(res2New)<- res2New[,1] res2New<- as.matrix(res2New[,-1]) dim(res2New) #[1] 28 28 head(res2New,3) # AgriEmi AgriMach AgriValAd AgrVaGDP AIL ALAre #AgriEmi NA 0.23401895 0.45697412 4.644877e-01 0.6398030 0.4039855 #AgriMach 0.2340189 NA 0.01449519 4.922558e-06 0.3890046 0.9279044 #AgriValAd 0.4569741 0.01449519 NA 5.135269e-02 0.5325943 0.4872555 # ALPer ANS AraLa AraLaPer CombusRen ForArea #AgriEmi 0.4039855 2.507257e-01 0.2303275 0.2303275 0.9438409125 0.0004473563 #AgriMach 0.9279044 6.072123e-05 0.3154370 0.3154370 0.0040254771 0.2590309747 #AgriValAd 0.4872555 2.060412e-01 0.8449600 0.8449600 0.0008077264 0.5152352072 # ForArePer ForProTon ForProTonSKm ForRen GDP #AgriEmi 0.0004473563 0.01714768 0.0007089448 0.900222038 0.6022470671 #AgriMach 0.2590309748 0.20170800 0.2305335762 0.005584703 0.4199684378 #AgriValAd 0.5152352071 0.80983446 0.4368256400 0.208975126 0.0003534226 # GEF GroAgriProVal PermaCrop RoadDens RoadTot RurPopGro #AgriEmi 0.0008580856 0.01078593 0.6863110 0.6398030 0.6398030 0.40734903 #AgriMach 0.1315182244 0.14074612 0.2530378 0.3064186 0.3064186 0.33705434 #AgriValAd 0.7520803684 0.31556633 0.1151395 0.4374599 0.4374599 0.04837586 # RurPopPerc TerrPA Trac Vehi WaterWith #AgriEmi 0.4835676 0.4504239 2.279566e-01 0.6398030 0.3056195 #AgriMach 0.6401556 0.1707857 4.730759e-33 0.3064186 0.9502553 #AgriValAd 0.2383507 0.0223124 1.513169e-02 0.1251843 0.3307148
#or res3<-xtabs(value~Var1+Var2,data=dat2) #here the diagonals are "0"s attr(res3,"class")<- NULL attr(res3,"call")<-NULL names(dimnames(res3))<-NULL #You can change it in the first solution also. res2New<- dcast(dat2,Var1~Var2,value.var="value",fill=0) row.names(res2New)<- res2New[,1] res2New<- as.matrix(res2New[,-1]) identical(res2New,res3) #[1] TRUE A.K. Arun, That does exactly what I wanted to do, but how would I manipulate into a matrix where the indepedent variable was on the x and dependent on y, or vice versa, rather than a 736, 2 matrix V1 V2 V3 V4 V5...Vn V1 - V2 - V3 - V4 - V5 - Vn - ----- Original Message ----- From: arun <smartpink...@yahoo.com> To: R help <r-help@r-project.org> Cc: Sent: Thursday, September 5, 2013 12:49 PM Subject: Re: Looping an lapply linear regression function 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.