Hi, It would be better to post a reproducible example.
set.seed(42) df1 <- cbind(as.data.frame(matrix(sample(60,40,replace=TRUE),ncol=4)),date=seq(as.Date("2013-05-10"),length.out=10,by=1)) colnames(df1)[-5] <- paste0("mod",1:4) set.seed(14) df2 <- data.frame(obs=1:20,wy=sample(12,20,replace=TRUE),date=seq(as.Date("2013-05-12"),length.out=20,by=3)) An <- c(colnames(df1),colnames(df2)) merge(df1,df2,by=c("date"))[,An[!duplicated(An,fromLast=TRUE)]] # mod1 mod2 mod3 mod4 obs wy date #1 18 57 60 24 1 4 2013-05-12 #2 32 57 31 50 2 8 2013-05-15 #3 40 29 27 55 3 12 2013-05-18 A.K. On Wednesday, January 15, 2014 4:44 PM, Janet Choate <jsc....@gmail.com> wrote: Hi, i am merging two data frames of different time periods, so that the result contains data from both for the same time period. however, I want the result to output columns in a certain order. the common column between the two data frames is date. for example: df1 columns: mod1 mod2 mod3 mod4 date #(there are actually 691 mod columns) df2 columns: obs wy date after merge, i want the order of the columns to be all mod data columns from df1, followed by the obs and wy columns from df2, followed by the date column. i almost get want i want with (at least it doesn't put the common column date as the first column as merge does by default): new = merge(df1, df2, by=c("date"))[, union(names(df1), names(df2))] however, that of course gives me all of df1 followed by all of df2, which doesn't put obs immediately after the mod columns: what i get: mod1 mod2 mod3 mod4 date obs wy what i want: mod1 mod2 mod3 mod4 obs wy date any suggestions on how to output the columns in the order i want, without having to rearrange the order after the fact? thank you for any help! Janet [[alternative HTML version deleted]] ______________________________________________ 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. ______________________________________________ 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.