search for: ididx

I have data.frame's with IDs and multiple columns. B/c some of IDs showed up more than once, I need sum up colum values to creat a new dataframe with unique ids. I hope there are some cheaper ways of doing it... Because the dataframe is huge, it takes almost an hour to do the task. Thanks so much in advance! Young # ------------------------- examples are here and sum.dup.r is at the