I am having trouble defining (and therefore searching) for this problem. I have data like this:
Group Value Date 1 xxx June 1 yyy July 2 zzzz May 2 qqqq August etc. I want to subset the 'Value' of each 'Group' by the latest 'Date'. So my output should be: Group Value Date 1 yyy July 2 qqqq August etc. The doBy package has a firstobs() function that works but is quite slow. What would be a data.table way to do this? Thank you, Ben -- View this message in context: http://r.789695.n4.nabble.com/Subsetting-By-Row-Function-tp4694221.html Sent from the datatable-help mailing list archive at Nabble.com. _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
