Advertisements I have a data set that looks like this: > newex Name Volume Period 1 oil 29000 Jun 21 2 gold 800 Mar 22 3 oil 21000 Jul 21 4 gold 1100 Sep 21 5 gold 3000 Feb 21 6 depower 3 Q1 21 7 oil 23000 Apr 22 8 czpower 26 Q1 23… Read More R Aggregate data frame based on column values