Hi Joshua, The code you put together is very helpful. I have run into a small issue, however, and I am surprised you weren't getting similar error message when you tried running the nested for loops? As an example, I've pared down the for loop a bit to highlight the error message I'm getting (note also that I had to modify xs[[i]]$Q to xs[[i]]$*x*Q):
for(i in seq_along(xs)) { for(j in seq_along(xs)) { xcov[paste0("Q",i),paste0("Q",j)] <- xcov[paste0("Q",j),paste0("Q",i)] <- cov(xs[[i]]$xQ, xs[[j]]$xQ, use="complete.obs") } } #Error in cov(xs[[i]]$xQ, xs[[j]]$xQ, use = "complete.obs") : # incompatible dimensions #Some investigation... i # 1 j # 95 length(xs[[i]]$xQ) # 96 length(xs[[j]]$xQ) # 92 xs[[j]]$xQ[1:10] # xQ #2004-04-04 00:00:00 674 #2004-04-04 00:15:00 669 #2004-04-04 00:30:00 664 #2004-04-04 00:45:00 664 #2004-04-04 01:00:00 669 #2004-04-04 01:15:00 659 #2004-04-04 01:30:00 674 #2004-04-04 01:45:00 669 #2004-04-04 03:00:00 664 #2004-04-04 03:15:00 674 xs[[i]]$xQ[1:10] # xQ #2004-01-01 00:00:00 0.43 #2004-01-01 00:15:00 0.43 #2004-01-01 00:30:00 0.43 #2004-01-01 00:45:00 0.43 #2004-01-01 01:00:00 0.57 #2004-01-01 01:15:00 0.57 #2004-01-01 01:30:00 0.57 #2004-01-01 01:45:00 0.43 #2004-01-01 02:00:00 0.43 #2004-01-01 02:15:00 0.57 I suppose the reason use="complete.obs", use="pair", or use="pairwise.complete.obs" won't work is because the date stamp is different despite the fact there are similar time stamps during the respective days. Thus, I'm wondering if there is a way to direct the cov function to make the calculation using only the time stamp (and not the date stamp) to determine pairs? Thanks, Eric -- View this message in context: http://r.789695.n4.nabble.com/Filling-a-covariance-matrix-tp4647170p4648015.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.