Hi, I am trying to select the first row of a variable with data in long-format, e.g.,
# sample data id <- c(1,1,1,2,2) value <- c(5,6,7,4,5) dat <- data.frame(id, value) dat How can I select/subset the first 'value' for each unique 'id'? Thanks, AC [[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.