Hi, Try ?merge() or ?join() from library(plyr) res<-merge(df1,df2,by="plot.id") head(res,6) # plot.id tree.tag load #1 plot1 111 17 #2 plot1 112 17 #3 plot1 113 17 #4 plot2 222 6 #5 plot2 223 6 #6 plot3 333 24 A.K>
----- Original Message ----- From: Sarah Haas <haaszool...@gmail.com> To: r-help@r-project.org Cc: Sent: Thursday, December 13, 2012 9:15 AM Subject: [R] Repeat elements of matrix based on vector counts I have two dataframes (df) that share a column header ("plot.id"). In the 1st df, "plot.id" records are repeated a variable number of times based on the number of trees monitored within each plot. The 2nd df only has a single record for each "plot.id", and contains a variable named "load" that is collected at the plot-level and is only listed once per plot record. *OBJECTIVE:* I need to repeat the "load" values from the 2nd df based on how many times "plot.id" is repeated in the 1st df (all plots are repeated a different number of times). My example dfs are below: ************************************************************************************************ df1 <- data.frame(plot.id = rep(c("plot1", "plot2", "plot3"), c(3,2,5)), tree.tag = c(111,112,113,222,223,333,334,335,336,337)) df2 <- data.frame(plot.id = c("plot1", "plot2", "plot3"), load=c(17, 6, 24)) ************************************************************************************************ I have gotten close to solving this, but alas I'm on day 2 of problem-shooting and can't get it! Thanks for any help you might provide. --Sarah [[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.