Whenever a task calls for breaking a data object into pieces, operate on the pieces, then put it back together, then think about using the plyr package.
Sent from my iPod On Dec 24, 2010, at 6:58 AM, "Ali Salekfard" <salekf...@googlemail.com> wrote: > Hi all, > > I'm new to the list but have benfited from it quite extensively. Straight to > my rather strange question: > > I have a data frame that contains mapping rules in this way: > > ACCOUNT, RULE COLUMNS, Effective Date > > > The dataframe comes from a database that stores all dates. What I would like > to do is to create a data frame with only the most recent rule for each > account. In traditional programming languages I would loop through each > account find the most recent rule(s) and fill up my updated data frame. > > Does anyone have any better idea to use R's magic (Its syntax is still > magical to me) for this problem? > > By the way the list of rules is quite extensive (144643 lines to be > precise), and there are usually 1-3 most recent rules (rows) for each > account. > > 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. ______________________________________________ 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.
