Hello, Check the function diff() it can do it for you, no need for a loop.
Cheers, Jonas Mandel ecvet...@uwaterloo.ca a écrit : > I have a data frame with 2 columns, one for day and one for average. The > day starts at 97 all the way to 279. I want to subtract day 98 average- > day 97 average, then day99 average -day 98 average and so on down my > list, creating another column with the subtracted results. > I have: > > Day DailyAverage > 1 97 0.6076782 > 2 98 0.7121478 > 3 99 0.8059347 > 4 100 0.9545806 > 5 101 1.0589791 > 6 102 1.1335981 > 7 103 1.2676922 > 8 104 1.4429847 > 9 105 1.6477266 > 10 106 1.7970784 > etc. with values to day 279 > > I'm guessing I need to create some kind of loop for this, but I am > unsure as to how to do this. Any help is greatly appreciated. > > Thanks, > Emilija > > ______________________________________________ > 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.