Hello, I would like to build a list through the following codes."know1" & "know2" are some list obtained before. "know1" has the length of 50 (as for i), "know2" has the lengh of 50 (as for i), know1[[i]] has the length of 1000, know2[[i]] has the length of 1132. I would like to get the list "finalreturnc", for which finalreturnc[[i]][[j]] =know1[[i]]*know2[[i]][j]. But the loop does not seem to work, eg, I got the follwing value of finalreturnc ....... [[50]][[1131]] NULL [[50]][[1132]] 1] -3.467047e-03 -2.963263e-02... finalreturnc <- list() volc1 <- list() for (i in 1:50){ for (j in 1:1132) { volc1[[j]] <- vector() volc1[[j]] <- know1[[i]]*know2[[i]][j] finalreturnc[[i]]<- list() finalreturnc[[i]][[j]]<- volc1[[j]] } } Could anyone give me some advice? Many thanks -- View this message in context: http://www.nabble.com/Loop-tf4712520.html#a13470236 Sent from the R help mailing list archive at Nabble.com.