Hi Eric, I think this does what you want. It may be a simple question, but that does not necessarily mean the easiest/fastest answer is intuitive. Welcome to R!
dat <- data.frame(v = 1:100) ## the with() is just a convenient way to avoid having to type ## dat$v every single time---similar to attach(), but cleaner ## the idea is to create three vectors, that are offset by removing ## either the first observation or the last with(dat, (v[-1] - v[-length(v)])/v[-length(v)]) HTH, Josh On Sun, Nov 28, 2010 at 7:29 PM, eric <ericst...@aol.com> wrote: > > Just starting to learn R so excuse me if this is a simple question. I'm > wondering how I get the percent difference in sequential values in one > column of a dataframe. If I had a dataframe and one of the columns was > "value", how would I go about calculating (v2-v1)/v1 ....(v3-v2)/v2 > ....(v4-v3)/v3 ...etc ? > -- > View this message in context: > http://r.789695.n4.nabble.com/How-do-I-subtract-sequential-values-tp3063019p3063019.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. > -- Joshua Wiley Ph.D. Student, Health Psychology University of California, Los Angeles http://www.joshuawiley.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.
