Hi, I am new to R so I would appreciate any help. I have some data that has passenger flight data between city pairs. The way I got the data, there are multiple rows of data for each city pair; the number of passengers needs to be summed to get a TOTAL annual passenger count for each city pair.
So my question is: how do I create a new table (or data frame) that selectively sums My initial thought would be to iterate through each row with the following logic: 1. If the ORIGIN_WAC and DEST_WAC pair are not in the new table, then add them to the table 2. If the ORIGIN_WAC and DEST_WAC pair already exist, then sum the passengers (and do not add a new row) Is this logical? If so, I think I just need some help on syntax (or do I use a script?). Thanks. The first few rows of data look like this: -- View this message in context: http://r.789695.n4.nabble.com/How-to-selectively-sum-rows-Beginner-question-tp3933512p3933512.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
