all problems solved. thank you for your help! for the sake of completeness, here my solution: #1) read in data: daten<-read.table('K:/Analysen/STRUCTURE/test.txt', header=TRUE, sep="\t") daten<-as.data.frame(daten)
#2) create empty matrix: indxind<-matrix(0,nrow=617, ncol=617) #indxind[1:20,1:19] #3) compare cells to each other, score: #for the whole dataset: s in 3:34, z1 in 1:617, z2 in 1:617 z1<-1 #running variable for rows in daten z2<-1 #running variable for rows in daten l1<-1 #running variable for rows in indxind l2<-1 #running variable for rows in indxind for (s in 3:6) { #walks though the matrix colum by colum, starting at colum 3 while (z1<11) { #for each current colum, take one row (z1)... while (z2<11) { #...and compare it to another row (z2) of the current colum if (z1!=z2) { l1 topf<-indxind[l1,l2] if (daten[z1,s]==daten[z2,s]) topf<-topf+1 #actually, 2 rows make up 1 individual, if (daten[z1,s]==daten[z2+1,s]) topf<-topf+1 #therefore i compare 2 rows if (daten[z1+1,s]==daten[z2,s]) topf<-topf+1 #with another 2 rows if (daten[z1+1,s]==daten[z2+1,s]) topf<-topf+1 indxind[l1,l2]<-topf } z2<-z2+2 l2<-l2+1 } z2<-1 l2<-1 z1<-z1+2 l1<-l1+1 } z1<-1 l1<-1 } #4) check: indxind[1:5,1:5] -- View this message in context: http://r.789695.n4.nabble.com/help-please-matrix-operations-inside-3-nested-loops-tp4639592p4639744.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.