> -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Nordlund, Dan (DSHS/RDA) > Sent: Monday, December 06, 2010 9:21 AM > To: r-help@r-project.org > Subject: Re: [R] How can I refer to actual (n) and previous (n-1) > elements in a vector? > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > > project.org] On Behalf Of Marianne Stephan > > Sent: Monday, December 06, 2010 9:13 AM > > To: r-help@r-project.org > > Subject: [R] How can I refer to actual (n) and previous (n-1) > elements > > in a vector? > > > > > > Hello, > > > > > > How can I apply a function on a vector that refers to actual (n) and > > previous elements in the vector (e.g. n-1)? > > > > > > For example: > > I would like to calculate the sum of (n-1) + n for each element of a > > vector and get a vector as a result. > > > > > > Besides others I tried this: > > > > > > v<-c(3,6,8,1,1,3,9,5,6,3) > > for (i in 1:NROW(v)){a[i]<-a[i-1]+a[i]} > > > > > > I would like to get this result: > > 9,14,9,2,4,12,14,11,9 > > > > > > I would greatly appreciate your help! > > Marianne > > [[alternative HTML version deleted]] > > How about something like > > v[-n] + v[-1] >
Sorry for the noise. That should have been v[-length(v)] + v[-1] Hope this is more helpful, Dan Daniel J. Nordlund Washington State Department of Social and Health Services Planning, Performance, and Accountability Research and Data Analysis Division Olympia, WA 98504-5204 ______________________________________________ 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.
