I take this case as cut a data set by breaks and assign each segment a label name.
a <- data.frame(timestamp=c(3,5,8), mylabel=c("abc","def","ghi")) b <- data.frame(timestamp=c(1:10)) bks <- c(a$timestamp,max(b$timestamp)) lbs <- a$mylabel b$label <- cut(b$timestamp, breaks=bks, labels=lbs, include.lowest = T, right=T) ----- A R learner. -- View this message in context: http://r.789695.n4.nabble.com/Merging-columns-along-time-line-tp2289147p2289395.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.