Hi all! I have a tibble regarding a series of comments on a forum; the tibble has a certain number of variables, and in particular:
id: comment id; author_id: author id; parent_id: if the message is a reply, the original comment id I want to add another column, in which I put the author id of the original comment, when parent_id IS NOT NA. I already tried to use mutate + ifelse but my problem is that I have to refer to an author id in a different row than that in which I'm evaluating the if condition... Thanks in advance, Alessandro [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.