Here is how you can do it with data.table: > x <- read.table(text = " author_id paper_id prob + 731 24943 1 + 731 24943 1 + 731 688974 1 + 731 964345 .8 + 731 1201905 .9 + 731 1267992 1 + 736 249 .2 + 736 6889 1 + 736 94345 .7 + 736 1201905 .9 + 736 126992 .8", header = TRUE) > require(data.table) > x <- data.table(x) > output <- x[ + , list(paper_id = paste(paper_id[order(prob, decreasing = TRUE)], collapse = ',')) + , keyby = author_id + ] > output author_id paper_id 1: 731 24943,24943,688974,1267992,1201905,964345 2: 736 6889,1201905,126992,94345,249 >
Jim Holtman Data Munger Guru What is the problem that you are trying to solve? Tell me what you want to do, not how you want to do it. On Thu, Mar 27, 2014 at 7:01 AM, Rohit Gupta <rhtgpt...@gmail.com> wrote: > I have a data A which looks like > > > author_id paper_id prob > 731 24943 1 > 731 24943 1 > 731 688974 1 > 731 964345 .8 > 731 1201905 .9 > 731 1267992 1 > 736 249 .2 > 736 6889 1 > 736 94345 .7 > 736 1201905 .9 > 736 126992 .8 > > The output I am desiring is: > > author_id paper_id > 731 24943,24943,688974,1201905,964345 > 736 6889,1201945,126992,94345,249 > > That is paper_id are arranged according to decreasing order of > probability.How could this be done? > > Thanks > > [[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. > [[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.
